Summary Prospectus by Investment Company (Form 497K)

INVESTMENT OBJECTIVE

The Fund seeks to provide investment results approximating the overall performance of the MSCI Emerging Markets Index (the "Index").

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. You may be required to pay commissions and/or other forms of compensation to a financial intermediary for transactions in Shares Class shares, which are not reflected in the tables or the examples below.

EXAMPLE

The following Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same (taking into account the expense reimbursement arrangement for one year). Although your actual costs may be higher or lower, based on these assumptions your costs would be:

PORTFOLIO TURNOVER. The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate 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 Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 17.87% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES

Under normal circumstances, the Fund will invest substantially all (and at least 80%) of its net assets in equity securities, in weightings that approximate the relative composition of the securities included in the Index, in American Depositary Receipts ("ADRs"), European Depositary Receipts ("EDRs"), and Global Depositary Receipts ("GDRs") representing such securities, and in MSCI Emerging Markets Index futures approved by the Commodity Futures Trading Commission. The Fund's common stock investments also include China A-shares (shares of companies based in mainland China that trade on the Shanghai Stock Exchange and the Shenzhen Stock Exchange).

The Index captures large and mid-cap representation across 24 Emerging Markets countries, as determined by the index provider, and covers approximately 85% of the free float-adjusted market capitalization in each country as of May 29, 2026. As of May 29, 2026, the Index was comprised of 1,205 constituents with market capitalizations ranging from $110.44 million to $1.85 trillion. It is rebalanced quarterly. The Fund generally rebalances its portfolio in accordance with the Index.

NTI uses a "passive" or indexing approach to try to achieve the Fund's investment objective. Unlike many investment companies, the Fund does not try to "beat" the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued. NTI will buy and sell securities in response to changes in the Index as well as in response to subscriptions and redemptions.

The Fund generally invests in substantially all of the securities in the Index in approximately the same proportion as the Index (i.e., replication). In certain circumstances, however, the Fund may not hold every security in the Index or in the same proportion as the Index, such as to improve tax efficiency or when it may not be practicable to fully implement a replication strategy. Rather, it will use an optimization strategy to seek to construct a portfolio that minimizes tracking error versus the Index while managing transaction costs and realized capital gains and losses.

Derivatives instruments that provide investment exposure to investments in the Fund's 80% investment policy and derivatives instruments that provide investment exposure to one or more of the market risk factors associated with such securities may be counted towards the Fund's 80% investment policy.

The Fund intends to be diversified in approximately the same proportion as the Index is diversified. The Fund may become "non-diversified," as defined in the Investment Company Act of 1940 (the "1940 Act"), solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the Index. A "non-diversified" fund can invest a greater percentage of its assets in a small group of issuers or in any one issuer than a diversified fund can. Shareholder approval will not be sought if the Fund becomes non-diversified due solely to a change in the relative market capitalization or index weighting of one or more constituents of the Index.

In seeking to track the performance of the Index, from time to time the Fund may have a focused investment (i.e., investment exposure comprising more than 15% of its total assets) in one or more particular sectors, countries and/or geographic regions. As of March 31, 2026, the Fund had focused investments in China, South Korea and Taiwan, and in the financials and information technology sectors.

NTI expects that, under normal circumstances, the quarterly performance of the Fund, before fees and expenses, will track the performance of the Index within a 0.95 correlation coefficient.

The Index is created and sponsored by Morgan Stanley Capital International, Inc. ("MSCI"), as the index provider. MSCI determines the composition and relative weightings of the securities in the Index and publishes information regarding the market value of the Index. MSCI does not endorse any of the securities in the Index. It is not a sponsor of the Emerging Markets Equity Index Fund and is not affiliated with the Fund in any way.

PRINCIPAL RISKS

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value ("NAV"), total return and ability to meet its investment objective. Each risk noted below is considered a principal risk of investing in the Fund, regardless of the order in which it appears. The significance of each risk factor below may change over time and you should review each risk factor carefully.

MARKET RISK is the risk that the value of the Fund's investments may increase or decrease in response to expected, real or perceived economic, political or financial events in the U.S. or global markets. The frequency and magnitude of such changes in value cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in response to changing market conditions, inflation, elevated levels of government debt, changes in interest rates, lack of liquidity in the bond or equity markets or volatility in the equity markets. Market disruptions caused by local or regional events such as financial institution failures, changes in trade regulation or economic sanctions, internal unrest and discord, war, acts of terrorism, the spread of infectious illness (including epidemics and pandemics) or other public health issues, recessions, the threat or occurrence of a government shutdown, or other events or adverse investor sentiment could have a significant impact on the Fund and its investments. During periods of market disruption or other abnormal market conditions, the Fund's exposure to risks described elsewhere in this summary will likely increase.

EMERGING MARKETS RISK is the risk that emerging markets are generally subject to greater market volatility, political, social and economic instability, uncertain trading markets and more governmental limitations on foreign investments than more developed markets. In addition, companies operating in emerging markets may be subject to lower trading volumes and greater price volatility than companies in more developed markets. Emerging market economies may be based on only a few industries, may be highly vulnerable to changes in local and global trade conditions, and may suffer from extreme and volatile debt burdens or inflation rates. Companies in emerging market countries generally may be subject to less stringent regulatory, disclosure, financial reporting, accounting, auditing and recordkeeping standards than companies in more developed countries. As a result, information, including financial information, about such companies may be less available and reliable, which can impede the Fund's ability to evaluate such companies. Securities law and the enforcement of systems of taxation in many emerging market countries may change quickly and unpredictably, and the ability to bring and enforce actions (including bankruptcy, confiscatory taxation, expropriation, nationalization of a company's assets, restrictions on foreign ownership of local companies, restrictions on withdrawing assets from the country, protectionist measures and practices such as share blocking), or to obtain information needed to pursue or enforce such actions, may be limited. Investments in emerging market securities may be subject to additional transaction costs, delays in settlement procedures, unexpected market closures, and lack of timely information.

FOREIGN SECURITIES RISK is the risk that investing in foreign (non-U.S.) securities may result in the Fund experiencing more rapid and extreme changes in value than a fund that invests exclusively in securities of U.S. companies, due to less liquid markets and adverse economic, political, diplomatic, financial,

and regulatory factors. Foreign governments may impose limitations on foreigners' ownership of interests in local issuers, restrictions on the ability to repatriate assets, and may also impose taxes. Any of these events could cause the value of the Fund's investments to decline. Foreign banks, agents and securities depositories that hold the Fund's foreign assets may be subject to little or no regulatory oversight over, or independent evaluation, of their operations. Additional costs associated with investments in foreign securities may include higher custodial fees than those applicable to domestic custodial arrangements and transaction costs of foreign currency conversions. Unless the Fund has hedged its foreign currency exposure, foreign securities risk also involves the risk of negative foreign currency rate fluctuations, which may cause the value of securities denominated in such foreign currency (or other instruments through which the Fund has exposure to foreign currencies) to decline in value. Currency exchange rates may fluctuate significantly over short periods of time. Currency hedging strategies, if used, are not always successful. For instance, forward foreign currency exchange contracts, if used by the Fund, could reduce performance if there are unanticipated changes in currency exchange rates.

GEOGRAPHIC RISK is the risk that if the Fund invests a significant portion of its total assets in certain issuers within the same country or geographic region, an adverse economic, business or political development affecting that country or region may affect the value of the Fund's investments more, and the Fund's investments may be more volatile, than if its investments were not so concentrated in such country or region.

DEPOSITARY RECEIPTS RISK Foreign securities may trade in the form of depositary receipts. In addition to investment risks associated with the underlying issuer, depositary receipts may expose the Fund to additional risks associated with non-uniform terms that apply to depositary receipt programs, including credit exposure to the depository bank and to the sponsors and other parties with whom the depository bank establishes the programs, currency, political, economic, market risks and the risks of an illiquid market for depositary receipts. Depositary receipts are generally subject to the same risks as the foreign securities that they evidence or into which they may be converted. Depositary receipts may not track the price of the

underlying foreign securities on which they are based, may have limited voting rights, and may have a distribution subject to a fee charged by the depository. As a result, equity shares of the underlying issuer may trade at a discount or premium to the market price of the depositary receipts.

TRACKING RISK is the risk that the Fund's performance may vary from the performance of the index it tracks as a result of share purchases and redemptions, transaction costs, expenses and other factors. Market disruptions, regulatory restrictions or other abnormal market conditions could have an adverse effect on the Fund's ability to adjust its exposure to required levels in order to track its Index or cause delays in the Index's rebalancing schedule. During any such delay, it is possible that the Index, and, in turn, the Fund will deviate from the Index's stated methodology and therefore experience returns different than those that would have been achieved under a normal rebalancing or reconstitution schedule.

SECTOR RISK is the risk that companies in similar businesses may be similarly affected by particular economic or market events, which may, in certain circumstances, cause the value of securities of all companies in a particular sector of the market to decrease.

MID CAP STOCK RISK is the risk that stocks of mid-sized companies may be more volatile than stocks of larger, more established companies, and may lack sufficient market liquidity. Mid-sized companies may have limited product lines or financial resources, may be dependent upon a particular niche of the market, or may be dependent upon a small or inexperienced management group. Securities of mid-sized companies may trade less frequently and in lower volume than the securities of larger companies, which could lead to higher transaction costs. Generally, the smaller the company size, the greater the risk.

INDEX RISK is the risk that that the Fund would not necessarily buy or sell a security unless that security is added or removed, respectively, from the Index, even if that security generally is underperforming, because unlike many investment companies, the Fund does not utilize an investing strategy that seeks returns in excess of the Index. Additionally, the Fund rebalances its portfolio in accordance with the Index, and, therefore, any changes to the Index's rebalance schedule will result in corresponding changes to the Fund's rebalance schedule.

DERIVATIVES RISK is the risk that derivatives may pose risks in addition to and greater than those associated with investing directly in securities, currencies and other instruments, may be illiquid or less liquid, more volatile, more difficult to value and leveraged so that small changes in the value of the underlying instrument may produce disproportionate losses to the Fund. Derivatives are also subject to counterparty risk, which is the risk that the other party to the transaction will not perform its contractual obligations. The use of derivatives is a highly specialized activity that involves investment techniques and risks different from those associated with investments in more traditional securities and instruments.

VALUATION RISK is the risk that the sale price the Fund could receive for a portfolio security may differ from the Fund's valuation of the security, particularly for securities that trade in low volume or volatile markets or that are valued using a fair value methodology. It is possible that the Fund could incur a loss because a portfolio security is sold at a discount to the value ascribed to it for purposes of calculating the Fund's net asset value. Fair value methodologies may involve more subjectivity than the use of market quotations when fair valuing an investment. In addition, the value of the securities in the Fund's portfolio may change on days when shareholders will not be able to purchase or sell the Fund's shares.

NON-DIVERSIFICATION RISK Under the 1940 Act, a fund designated as "diversified" must limit its holdings such that the securities of issuers which individually represent more than 5% of its total assets must in the aggregate represent less than 25% of its total assets. The Fund is "diversified" for purposes of the 1940 Act. However, in seeking to track its Index, the Fund may become "non-diversified," as defined in the 1940 Act, solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the Index. A non-diversified fund can invest a greater portion of its assets in the obligations or securities of a small portion of its assets in the obligations or securities of a small number of issuers or any single issuer than a diversified fund can. In such circumstances, a change in the value of one or a few issuers' securities will therefore affect the value of the Fund more than if it was a diversified fund.

SECURITIES LENDING RISK is the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral.

As with any mutual fund, it is possible to lose money on an investment in the Fund. An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation, any other government agency, or The Northern Trust Company, its affiliates, subsidiaries or any other bank.

FUND PERFORMANCE

The bar chart and table that follow provide an indication of the risks of investing in the Fund by showing (A) changes in the performance of the Fund from year to year, and (B) how the average annual total returns of the Fund compare to those of a broad-based securities market index.

The Fund's past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future.

Updated performance information for the Fund is available and may be obtained on the Fund's website at northerntrust.com/funds or by calling 800-595-9111.

CALENDAR YEAR TOTAL RETURN*

* Year to date total return for the six months ended June 30, 2026 was 25.64%. For the periods shown in the bar chart above, the highest quarterly return was 19.07% in the fourth quarter of 2020, and the lowest quarterly return was (24.06)% in the first quarter of 2020.

AVERAGE ANNUAL TOTAL RETURN

(For the periods ended December 31, 2025)

After-tax returns 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. After-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.

In calculating the federal income taxes due on redemptions, capital gains taxes resulting from redemptions are subtracted from the redemption proceeds and the tax benefits from capital losses resulting from the redemptions are added to the redemption proceeds. Under certain circumstances, the addition of the tax benefits from capital losses resulting from redemptions may cause the Returns after taxes on distributions and sale of Fund shares to be greater than the Returns after taxes on distributions or even the Returns before taxes.

MANAGEMENT

INVESTMENT ADVISER AND PORTFOLIO MANAGERS. NTI, an indirect subsidiary of Northern Trust Corporation, serves as the investment adviser of the Emerging Markets Equity Index Fund. Robert D. Anstine, Senior Vice President of NTI, Brendan Sullivan, CFA, Senior Vice President of NTI, Yair Walny, CFA, Vice President of NTI, and Steven J. Santiccioli, Vice President of NTI, have been managers of the Fund since July 2019, September 2024, July 2025, and September 2024, respectively. The Northern Trust Company, an affiliate of NTI, serves as transfer agent, custodian, securities lending agent, and sub-administrator to the Fund.

PURCHASE AND SALE OF FUND SHARES

You may purchase Shares Class shares of the Fund by opening an account directly with Northern Funds (the "Trust") with a minimum initial investment of $2,500 in the Fund ($500 for an IRA; $250 under the Automatic Investment Plan; and $500 for employees of Northern Trust and its affiliates). The minimum subsequent investment is $50 (except for reinvestments of distributions for which there is no minimum). The Fund reserves the right to waive these minimums. You may also purchase Shares Class shares of the Fund through an account at Northern Trust (or an affiliate) or an authorized intermediary.

If you purchase, sell (redeem) or exchange Shares Class shares through an authorized intermediary, you may be required to pay a commission and/or other forms of compensation to the intermediary. In addition, an authorized intermediary may impose different investment minimums than those set forth above. The Fund is not responsible for any investment minimums imposed by authorized intermediaries or for notifying shareholders of any changes to them.

On any business day, you may sell (redeem) or exchange shares through your account by contacting your Northern Trust account representative or authorized intermediary. If you purchase shares directly from the Trust, you may sell (redeem) or exchange your shares in one of the following ways:

TAX INFORMATION

The Fund's distributions are generally taxable to you as ordinary income, qualified dividend income, capital gains, or a combination of the three, unless you are investing through a tax-exempt or tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account. Distributions may be taxable upon withdrawal from tax-advantaged accounts.

PAYMENTS TO BROKERS-DEALERS AND OTHER FINANCIAL INTERMEDIARIES

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