Sumitomo Mitsui Trust Holdings, Inc. (三井住友トラスト・ホールディングス株式会社, Mitsui Sumitomo Torasuto Hōrudingusu Kabushiki Gaisha), formerly Chuo Mitsui Trust Holdings, Inc., is a Japanese financial holding company headquartered in Chiyoda, Tokyo. It provides an assortment of financial products to retail and wholesale customers, with a focus on asset management, financial brokerage and real estate services.

Its main operating company is Sumitomo Mitsui Trust Bank, Limited (三井住友信託銀行株式会社, Mitsui Sumitomo Shintaku Ginkō Kabushiki Gaisha), which is the largest trust company and the fifth-largest bank in Japan measured by assets.

The company has no capital relationship with the Sumitomo Mitsui Financial Group; the two banking groups are similarly named because both are descended from the historical Sumitomo and Mitsui conglomerates.

There is just a weak control relationship between Sumitomo Mitsui Trust Holdings and Sumitomo Mitsui Financial Group. In fact SM Trust Holdings controls about 66% of Japan Trustee Services Bank. As of March 31, 2017, SM Financial Group's website reports that Japan Trustee Services Bank owned 5.50% of Sumitomo Mitsui Financial Group, but also 1.52% from trust location n. 1 (信託口1), 1.50% from trust location n. 2 (信託口2), 2.05% from location n. 5 (信託口5), 1.36% from trust location n. 7 (信託口7), and 1.85% from trust location n. 9 (信託口9) as well.