史蒂芬·约书亚·桑坦（Stephen Joshua Sondheim，1930年3月22日－），又译为斯蒂芬·桑德海姆，是美国著名音乐剧及电影音乐作曲家及作词家，曾经获得奥斯卡最佳原创歌曲奖，七次托尼奖（Tony Awards），托尼奖戏剧终生成就奖，多次葛莱美奖项（Grammy Awards）以及普立兹戏剧奖（Pulitzer Prize）。他被誉为是「美国音乐剧界最重要及最具知名度的人物」。他包办作曲及作词的著名音乐剧有《理发师陶德》、《春光满古城》、《伙伴们》（company）、《痴人大秀》、《小夜曲》、《与佐治在公园的星期天》、《拜访森林》以及《刺杀》等等，而负责作词的音乐剧则有《西城故事》以及《吉卜赛人》。他是美国剧作家协会1973年至1981年的主席。

Stephen Joshua Sondheim (/ˈsɒnd.haɪm/) (born March 22, 1930) is an American composer and lyricist known for more than a half-century of contributions to musical theatre. Sondheim has received an Academy Award, eight Tony Awards (more than any other composer, including a Special Tony Award for Lifetime Achievement in the Theatre), eight Grammy Awards, a Pulitzer Prize, the Laurence Olivier Award, and a 2015 Presidential Medal of Freedom. He has been described by Frank Rich of The New York Times as "now the greatest and perhaps best-known artist in the American musical theater." His best-known works as composer and lyricist include A Funny Thing Happened on the Way to the Forum, Company, Follies, A Little Night Music, Sweeney Todd, Sunday in the Park with George, and Into the Woods. He wrote the lyrics for West Side Story and Gypsy.