Summary Prospectus by Investment Company (Form 497K)

DFA INVESTMENT DIMENSIONS GROUP INC.

	Class:	Ticker:	Exchange:
DFA Short-Term Municipal Bond Portfolio	ETF Class shares	DFSM	The Nasdaq Stock Market LLC

Summary Prospectus

August 30, 2026

Before you invest, you may want to review the Portfolio's ETF Class shares Prospectus, which contains more information about the Portfolio and its risks. You can find the Portfolio's ETF Class shares Prospectus and other information about the Portfolio, including the Statement of Additional Information (SAI) and most recent reports to shareholders, when available, online at https://www.dimensional.com/us-en/document-center. You can also get this information at no cost by calling collect to (512) 306-7400 or by sending an e-mail request to [email protected]. The Portfolio's ETF Class shares Prospectus and SAI, both dated August 30, 2026, as may be supplemented, are incorporated by reference into this Summary Prospectus. The Portfolio's ETF Class shares are listed on a national securities exchange and, unlike mutual fund shares, are not individually redeemable. In addition to the ETF Class shares, the Portfolio also offers a conventional mutual fund share class in a separate summary prospectus.

Investment Objective

The investment objective of the DFA Short-Term Municipal Bond Portfolio (the "Short-Term Municipal Bond Portfolio" or the "Portfolio") is to provide current income that is exempt from federal personal income taxes and to preserve investors' principal.

Fees and Expenses of the Portfolio

This table describes the fees and expenses you may pay if you buy, hold or sell ETF Class shares of the Portfolio. You may also incur usual and customary brokerage commissions when buying or selling the ETF Class shares of the Portfolio, which are not reflected in the table or Example that follows.

Shareholder Fees (fees paid directly from your investment): None
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Management Fee		0.15%
Other Expenses1		0.05%
Total Annual Fund Operating Expenses		0.20%
Fee Waiver and/or Expense Reimbursement2		0.01%
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.19%

1	The ETF Class shares of the Portfolio are new, so the "Other Expenses" shown for the class are based on anticipated fees and expenses for the first full fiscal year.
2	Dimensional Fund Advisors LP (the "Advisor") has agreed to waive certain fees and in certain instances, assume certain expenses of the ETF Class shares of the Portfolio. The Fee Waiver and/or Expense Assumption Agreement for the Portfolio will remain in effect through February 28, 2028, and may only be terminated by the Fund's Board of Directors prior to that date. Under certain circumstances, the Advisor retains the right to seek reimbursement for any fees previously waived and/or expenses previously assumed up to thirty-six months after such fee waiver and/or expense assumption.

EXAMPLE

This Example is meant to help you compare the cost of investing in the Portfolio's ETF Class shares with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Portfolio's ETF Class shares for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. The costs for the Portfolio's ETF Class shares reflect the net expenses of the Portfolio's ETF Class shares that result from the contractual expense waiver in the first year only. Although your actual costs

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may be higher or lower, based on these assumptions your costs whether you redeem or hold your shares would be:

1 Year	3 Years	5 Years	10 Years
$19	$63	$112	$254

PORTFOLIO TURNOVER

A fund generally pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Portfolio's performance. During the most recent fiscal year, the Portfolio's portfolio turnover rate was 198% of the average value of its investment portfolio.

Principal Investment Strategies

The Short-Term Municipal Bond Portfolio seeks its investment objective by investing primarily in a universe of investment grade municipal securities, the interest on which is exempt from regular federal income tax. Municipal securities in which the Portfolio may invest include, among others, revenue bonds, general obligation bonds, industrial development bonds, municipal lease obligations, commercial paper, variable rate demand obligations and other instruments (including participation interests in such securities) issued by or on behalf of the states, territories and possessions of the United States (including the District of Columbia) and their political subdivisions, agencies and instrumentalities. The interest on the municipal securities purchased by the Portfolio, in the opinion of bond counsel for the issuers and under current tax law, is exempt from federal income tax (i.e., excludable from gross income for individuals for federal income tax purposes but not necessarily exempt from state or local taxes). As a fundamental investment policy, under normal market conditions, the Portfolio will invest at least 80% of its net assets in municipal securities that pay interest exempt from federal income tax. The Portfolio does not currently intend to invest its assets in municipal securities whose interest is subject to the federal alternative minimum tax.

Generally, the Short-Term Municipal Bond Portfolio will acquire obligations that mature within three years from the date of settlement, but substantial investments may be made in obligations maturing up to ten years from the date of settlement when greater expected returns are available, and in variable rate demand obligations with longer maturities. Under normal circumstances, the Portfolio will maintain a weighted average effective maturity of three years or less. The effective maturity adjusts the stated final maturity of a fixed income security for an actual or expected event such as a call, put, tender, mandatory early redemption, pre-refunding, coupon or interest rate reset, or other similar event. In making purchase decisions, if the

DFA Short-Term Municipal Bond Portfolio	3

expected term premium is greater for longer-term securities in the eligible maturity range, Dimensional Fund Advisors LP (the "Advisor") will focus investment in the longer-term area, otherwise, the Portfolio will focus investment in the shorter-term area of the eligible maturity range. If a security has been or is expected to be redeemed by the issuer at a date prior to the stated final maturity date for the purposes of the above maturity restriction, the early redemption date shall be considered the maturity date regardless of the stated final maturity. If a security's coupon or interest rate is periodically reset, the reset date will be considered for the purposes of the above duration restriction.

At least 75% of the assets of the Short-Term Municipal Bond Portfolio will be invested in municipal securities that, at the time of purchase, are rated in the top three credit-rating categories (e.g., Aaa, Aa and A for Moody's Ratings ("Moody's") or AAA, AA and A for S&P Global Ratings ("S&P") or Fitch Ratings Ltd. ("Fitch"), or an equivalent rating assigned by another nationally recognized statistical rating organization, or that are unrated but have been determined by the Advisor to be of comparable quality). No more than 25% of the Portfolio's assets will be invested in municipal securities that, at the time of purchase, are rated in the lowest quarter of the investment grade spectrum (e.g., rated Baa1 to Baa3 (by Moody's) or BBB+ to BBB- (by S&P or Fitch), or an equivalent rating assigned by another nationally recognized statistical rating organization, or that are unrated but have been determined by the Advisor to be of comparable quality). The fixed income securities in which the Portfolio invests are considered investment grade at the time of purchase.

Municipal securities are often issued to obtain funds for various public purposes, including the construction of a wide range of public facilities, such as bridges, highways, housing, hospitals, mass transportation facilities, schools, streets and public utilities, such as water and sewer works. Municipal securities include municipal leases, certificates of participation, municipal obligation components and municipal custody receipts. The Short-Term Municipal Bond Portfolio may invest more than 25% of its assets in municipal securities issued to finance projects in a particular segment of the bond market including, but not limited to, health care, housing, education, utilities, and transportation. The Portfolio also may invest more than 25% of its assets in industrial development bonds.

The Short-Term Municipal Bond Portfolio may (1) purchase certain municipal securities that are insured, (2) invest in municipal securities secured by mortgages on single-family homes and multi-family projects, (3) invest in pre-refunded municipal securities, (4) purchase tax-exempt municipal securities on a "when-issued" basis, and (5) use derivatives, such as fixed income related futures and options contracts, credit default swaps, and interest rate swaps, to hedge against changes in interest rates. The Portfolio may also invest in exchange-traded funds (ETFs) to gain exposure to the municipal bond market pending investment in municipal bonds. The Portfolio may also invest in money market funds. The Portfolio also may purchase or sell futures contracts and options on futures contracts, to hedge its interest rate exposure or for non-hedging purposes, such as a substitute for direct investment or to increase

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or decrease market exposure based on actual or expected cash inflows to or outflows from the Portfolio.

Although the Short-Term Municipal Bond Portfolio attempts to invest all of its assets in tax-exempt securities, it is possible, although not anticipated, that a portion of its assets may be invested in securities that pay taxable interest, including interest that may be subject to the federal alternative minimum tax. These investments could generate taxable income for shareholders.

The Short-Term Municipal Bond Portfolio's ETF Class operates as an actively managed exchange-traded fund ("ETF") and does not seek to replicate the performance of a specific index and may have a higher degree of portfolio turnover than passively managed index ETFs.

Principal Risks

Because the value of your investment in the Portfolio will fluctuate, there is the risk that you will lose money. An investment in the Portfolio is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a description of principal risks of investing in the Portfolio.

Market Risk: Even a long-term investment approach cannot guarantee a profit. Economic, market, environmental, political, and issuer-specific conditions and events will cause the value of securities, and a fund that owns them, to rise or fall.

Interest Rate Risk: Fixed income securities are subject to interest rate risk because the prices of fixed income securities tend to move in the opposite direction of interest rates. When interest rates rise, fixed income security prices fall. During periods of very low or negative interest rates, a fund may be subject to a greater risk of rising interest rates. When interest rates fall, fixed income security prices rise. In general, fixed income securities with longer maturities are more sensitive to changes in interest rates.

Credit Risk: Credit risk is the risk that the issuer of a security, including a governmental entity, may be unable to make interest payments and/or repay principal when due. A downgrade to an issuer's credit rating or a perceived change in an issuer's financial strength may affect a security's value, and thus, impact the performance of a fund holding such securities. The ability of a municipal securities issuer to make payments could be affected by litigation, legislation or other political events or the bankruptcy of the issuer.

Income Risk: Income risk is the risk that falling interest rates will cause a fund's income to decline because, among other reasons, the proceeds from maturing short-term securities in its portfolio may be reinvested in lower-yielding securities.

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Call Risk: Call risk is the risk that during periods of falling interest rates, an issuer will call or repay a higher-yielding fixed income security before its maturity date, forcing a fund to reinvest in fixed income securities with lower interest rates than the original obligations.

Tax Liability Risk: Tax liability risk is the risk that distributions by a fund become taxable to shareholders due to noncompliant conduct by a municipal bond issuer, unfavorable changes in federal or state tax laws, or adverse interpretations of tax laws by the Internal Revenue Service or state tax authorities or other factors. Such adverse interpretations or actions could cause interest from a security to become taxable, possibly retroactively, subjecting shareholders to increased tax liability. In addition, such adverse interpretations or actions could cause the value of a security, and therefore, the value of a fund's shares, to decline.

Municipal Securities Risk: The risk of a municipal security generally depends on the financial and credit status of the issuer. Municipal securities can be significantly affected by political, regulatory or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer's insolvency. The municipal securities market can be susceptible to increases in volatility and decreases in liquidity. The secondary market for certain municipal securities tends to be less well developed or liquid than many other securities markets, which may adversely affect a fund's ability to sell such municipal securities at attractive prices. Liquidity can decline unpredictably in response to overall economic conditions or credit tightening. In addition, there may be less publicly available information about the financial condition of municipal security issuers than for issuers of other types of securities, making the securities more difficult to value. The price a fund could receive upon the sale of a portfolio investment may differ from the fund's valuation of the investment, particularly for investments that trade in thin or volatile markets or that are valued using a fair valuation methodology.

Municipal Project-Specific Risk: A fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in municipal securities that finance similar types of projects in a segment of the municipal bond market (such as education, health care, housing, education, utilities or transportation) or industrial development bonds. A change that affects one project in a particular segment of the market, such as proposed legislation on the financing of the project, a shortage of the materials needed for the project, or a declining need for the project, would likely affect all similar projects, thereby increasing market risk.

Variable Rate Demand Obligations Risk: Certain variable rate demand obligations ("VRDOs") may not have an active secondary market. These VRDOs could be difficult to dispose of if the remarketing agent defaults on its payment obligation and/or if the fund is not entitled to exercise its demand rights, which could cause a loss with respect to such VRDOs.

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Derivatives Risk: Derivatives are instruments, such as swaps, futures contracts, and options thereon, whose value is derived from that of other assets, rates or indices. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. Hedging with derivatives may increase expenses, and there is no guarantee that a hedging strategy will work. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains or cause losses if the market moves in a manner different from that anticipated by a fund or if the cost of the derivative outweighs the benefit of the hedge. The use of derivatives for non-hedging purposes may be considered to carry more risk than other types of investments. When a fund uses derivatives, the fund will be directly exposed to the risks of those derivatives. Derivative instruments are subject to a number of risks including counterparty, liquidity, interest rate, market, credit and management risks, as well as difficulties with respect to valuation. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and a fund could lose more than the principal amount invested. Additional risks are associated with the use of swaps including counterparty and credit risk (the risk that the other party to a swap agreement will not fulfill its contractual obligations, whether because of bankruptcy or other default) and liquidity risk (the possible lack of a secondary market for the swap agreement). Credit risk increases when a fund is the seller of swaps and counterparty risk increases when the fund is a buyer of swaps. In addition, where a fund is the seller of swaps, it may be required to liquidate portfolio securities at inopportune times in order to meet payment obligations. Swaps may be illiquid or difficult to value. Additionally, payments made or received by a fund under such derivatives may increase the amount of distributions taxable to you as ordinary income, increase or decrease the amount of capital gain distributions to you and/or decrease the amount available for distribution to you as exempt-interest dividends.

High Portfolio Turnover Risk: When high portfolio turnover (more than 100%) is caused by the sale of a fund's portfolio securities and the reinvestment by the fund in other portfolio securities, such high portfolio turnover may result in increased transaction costs, including brokerage commissions, dealer mark-ups and other transaction costs. Additionally, the sale of a fund's portfolio securities may result in the distribution of higher capital gains as compared to a fund with less active trading policies. Alternatively, for fixed income funds, a higher portfolio turnover may be in part the result of bonds being held to their maturity, which may have a minimal impact on transaction costs and taxes.

Liquidity Risk: Liquidity risk exists when particular portfolio investments are difficult to purchase or sell. To the extent that a fund holds illiquid investments, the fund's performance may be reduced due to an inability to sell the investments at opportune prices or times. Liquid portfolio investments may become illiquid or less liquid after purchase by a fund due to low trading volume, adverse investor perceptions, credit tightening and/or other market developments. Liquidity risk includes the risk that a fund will experience significant net redemptions at a time when it cannot find willing buyers for its portfolio securities or can only sell its portfolio securities at a material loss or at increased costs. Liquidity risk can be more pronounced in periods of market turmoil or in situations where ownership of shares of a fund are concentrated in one

DFA Short-Term Municipal Bond Portfolio	7

or a few investors. Investments that are illiquid or that trade in lower volumes may be more difficult to value.

Operational Risk: Operational risks include human error, changes in personnel, system changes, faults in communication, and failures in systems, technology, or processes, and the use of artificial intelligence and machine learning ("AI"). Various operational events or circumstances are outside a fund's or its advisor's control, including instances at third parties. A fund and its advisor seek to reduce these operational risks through controls and procedures. However, measures that seek to reduce these operational risks through controls and procedures may not address every possible risk and may be inadequate to address these risks.

Cyber Security Risk: A fund and its service providers' use of internet, technology and information systems may expose the fund to potential risks linked to cyber security breaches of those technological or information systems. Cyber security breaches, amongst other things, could allow an unauthorized party to gain access to proprietary information, customer data, or fund assets, or cause the fund and/or its service providers to suffer data corruption or lose operational functionality.

The following is a description of additional principal risks of investing in the ETF Class shares of the Portfolio, due to the shares being listed and traded on a national securities exchange.

Market Trading Risk: Active trading markets for ETF Class shares may not be developed or maintained by market makers or authorized participants. Authorized participants are not obligated to make a market in ETF Class shares or to submit purchase or redemption orders for creation units, which may widen bid-ask spreads. Trading in shares on an exchange may be halted in certain circumstances. There can be no assurance that the requirements of the listing exchange necessary to maintain the listing of ETF Class shares will continue to be met. Additionally, in stressed market conditions, the market for ETF Class shares may become less liquid in response to deteriorating liquidity in the markets for the fund's portfolio holdings, which may cause a significant variance in the market price of ETF Class shares and their underlying value as well as an increase in ETF Class shares' bid-ask spread.

Premium/Discount Risk: The net asset value ("NAV") of ETF Class shares and the value of your investment may fluctuate. Disruptions to creations and redemptions or the market price of a fund's holdings, the existence of extreme market volatility or potential lack of an active trading market for shares may widen bid-ask spreads and result in shares trading at a significant premium or discount to NAV. If a shareholder purchases shares at a time when the market price is at a premium to the NAV or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses.

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Performance

The bar chart and table immediately following illustrate the variability of the Portfolio's returns and are meant to provide some indication of the risks of investing in the Portfolio. The ETF Class shares of the Portfolio are a new class of shares for which performance information is not available, and therefore, for periods prior to the inception of the ETF Class shares, the bar chart and table show performance information for the Institutional Class shares of the Portfolio, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns of the ETF Class shares of the Portfolio may vary from the returns of the Institutional Class shares due to differences in expenses. The bar chart shows the changes in performance of the Institutional Class shares of the Portfolio from year to year. The table illustrates how annualized returns of the Institutional Class shares of the Portfolio for certain periods, both before and after taxes, compare with those of a broad measure of market performance. The table also includes the performance of an additional index with a similar investment universe as the Portfolio. The Portfolio's past performance (before and after taxes) is not an indication of future results. Updated performance information for the Portfolio can be obtained by visiting https://www.dimensional.com/us-en/funds.

The after-tax returns presented in the table for the Portfolio are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown in the table. In addition, the after-tax returns shown are not relevant to investors who hold shares of the Portfolio through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.

DFA Short-Term Municipal Bond Portfolio	9

DFA Short-Term Municipal Bond Portfolio Institutional Class Shares1 -Total Returns

January 2016-December 2025
Highest Quarter	Lowest Quarter
1.36% 2023, Q4	-0.96% 2022, Q3

Year-to-date returns as of June 30, 2026: 1.16%

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Annualized Returns (%) Periods ended December 31, 2025
			1 Year		5 Years		10 Years
DFA Short-Term Municipal Bond Portfolio - Institutional Class Shares
	Return Before Taxes		2.93%		1.65%		1.31%
	Return After Taxes on Distributions		2.93%		1.65%		1.31%
	Return After Taxes on Distributions and Sale of Portfolio Shares		2.85%		1.65%		1.31%
ICE BofA 1-3 Years US Municipal Securities Index2
(reflects no deduction for fees, expenses or taxes)			3.72%		1.56%		1.59%
S&P National AMT-Free Municipal Bond Index
(reflects no deduction for fees, expenses or taxes on sales)			3.77%		0.84%		2.28%
1.	As of December 31, 2025, the ETF Class shares of the Portfolio had not yet incepted. Performance shown prior to the inception date of the ETF Class shares is from the Portfolio's Institutional Class shares, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns for the ETF Class shares and Institutional Class shares may vary due to differences in their expenses.
2.	ICE BofA index data copyright 2025 ICE Data Indices, LLC. Prior to July 1, 2022, index returns reflect no deduction for transaction costs. Effective July 1, 2022, index returns include transaction costs (as determined and calculated by the index provider), which may be higher or lower than the actual transaction costs incurred by the Portfolio.

Investment Advisor/Portfolio Management

Dimensional Fund Advisors LP serves as the investment advisor for the Portfolio. The following individuals are responsible for leading the day-to-day management of the Portfolio:

• David A. Plecha, Global Head of Fixed Income Portfolio Management, member of the Investment Committee, Vice President, and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since inception (2002).

• Joseph F. Kolerich, Head of Fixed Income, Americas, member of the Investment Committee, Vice President, and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2012.

• Travis A. Meldau, Vice President and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2015.

Purchase and Sale of Shares

The Portfolio issues (or redeems) ETF Class shares at NAV only to certain financial institutions that have entered into agreements with the Portfolio's distributor in large

DFA Short-Term Municipal Bond Portfolio	11

aggregated blocks known as "Creation Units." A Creation Unit of the Portfolio's ETF Class shares consists of 50,000 shares. Creation Units are generally issued (or redeemed) in exchange for cash or in-kind for securities and a specified amount of cash that the Portfolio specifies each day at the NAV next determined after receipt of an order.

Individual ETF Class shares of the Portfolio may only be purchased and sold on The Nasdaq Stock Market LLC, other national securities exchanges, electronic crossing networks and other alternative trading systems through your broker-dealer at market prices and are not individually redeemable from the Portfolio. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares (bid) and the lowest price a seller is willing to accept for shares (ask) when buying or selling shares in the secondary market (the "bid-ask spread"). Because the Portfolio's ETF Class shares trade at market prices rather than at NAV, ETF Class shares may trade at a price less than (discount) or greater than (premium) the NAV of the ETF Class shares. Recent information, including information on the ETF Class shares' NAV, market price, premiums and discounts, and bid-ask spreads, is available on the Portfolio's website at https://www.dimensional.com/us-en/funds.

Tax Information

The distributions you receive from the Portfolio primarily are exempt from regular federal income tax. A portion of these distributions, however, may be subject to the federal alternative minimum tax and state and local taxes. The Portfolio may also make distributions that are taxable to you as ordinary income or capital gains.

Payments to Financial Intermediaries

If you purchase the Portfolio through a broker-dealer or other financial intermediary (such as a bank), the Portfolio and its related companies may pay the intermediary for the sale of the Portfolio shares and/or related services. These payments may create a conflict of interest by influencing the financial intermediary to recommend the Portfolio over another investment. Ask your financial advisor or visit your financial intermediary's website for more information.

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Dimensional Fund Advisors LP 6300 Bee Cave Road, Building One Austin, TX 78746 (512) 306-7400
DFA-083126-DFSM