Sumitomo Mitsui Financial Group, Inc. (株式会社三井住友フィナンシャルグループ), initialed as SMFG until 2018 and SMBC Group since, is a major Japanese multinational financial services group and holding company. It is the parent of Sumitomo Mitsui Banking Corporation (SMBC), SMBC Trust Bank, and SMBC Nikko Securities. SMBC originates from the 2001 merger of Sumitomo Bank with the Sakura Bank, itself a successor to the Mitsui Bank, and the group holding entity was created in December 2002 after which SMBC became its wholly owned subsidiary.

SMBC Group operates in retail, corporate, and investment banking segment worldwide. It provides financial products and services to a wide range of clients, including individuals, small and medium-sized enterprises, large corporations, financial institutions and public sector entities. It operates in over 40 countries and maintains a presence in all International Financial Centres as the 12th biggest bank in the world by total assets. It is one of the largest global financial institutions in project finance space by total loan value. It is headquartered in the Marunouchi neighborhood of Tokyo.

SMBC Group is the second-largest of Japan's three so-called megabanks, with $2 trillion of total assets at end-March 2023, behind Mitsubishi UFJ Financial Group ($2.9 trillion) and just ahead of Mizuho Financial Group ($1.9 trillion). As of 2024, SMBC group was listed as 63rd largest public company in the world according to Forbes Global 2000 ranking. It is considered a systemically important bank by the Financial Stability Board.

SMBC was formed by the merger of the Sumitomo Bank and Sakura Bank in April 2001. Its history could be viewed as going back to 1683, the date of first documented banking operations by Mitsui Takatoshi. The group's two main historical components, Mitsui Bank and Sumitomo Bank, were established as modern private banks in the Meiji era, in 1875 and 1895 respectively. SMBC Group also incorporates several of the National Banks in Meiji Japan which were numbered in accordance with their chronological date of establishment until 1880:

At the time of the merger, the combined entity was of similar size to Deutsche Bank and to the pending merger that would soon form Mizuho Bank.

The newly created bank was plagued with bad assets from the Japanese banking crisis. This led to several corporate actions taken by SMBC to clean up its balance sheet and raise capital, including writing off non-performing loans and selling its stake in Goldman Sachs.

SMBC announced on July 30, 2002 that it would establish a holding company by December and reorganize three related companies, its subsidiary Sumitomo Mitsui Card Company, Sumitomo Mitsui Bank Leasing, and The Japan Research Institute, a sister think tank, as subsidiaries of the holding company. The holding company had a capital of 1 trillion yen, and SMBC CEO Takashi Nishikawa and Chairman Akira Okada each served as president and chairman of the holding company.

In July 2002, SMBC announced that it would repay 2,000 billion yen of public funds, which had been accepted in the form of perpetual subordinated bonds. The funds were part of a total of 1.5 trillion yen that had been injected into the Japanese banking system following the financial crisis of the late 1990s. In 2005, SMBC announced a three-year repayment plan, and in October of that year, it repaid an additional 323.6 billion yen. SMFG initially targeted repaying all of its public funds by the end of the 2006 fiscal year. Mitsubishi UFJ Financial Group (MUFG) and Mizuho Financial Group (MHFG) also had the same goal. These moves were due to a number of factors, including the active resolution of non-performing loans, which had stabilized the financial system, and the increased repayment capacity of the banks. The Financial Services Agency had also encouraged banks to repay their funds early, and some banks, which were reluctant to have their management interfered with by the authorities, had responded.