Gustav Gerson Kahn (November 6, 1886 - October 8, 1941) was a famous German-American musician and songwriter.

Born in Coblenz, Germany , Kahn and his family moved to Chicago, Illinois in 1890. His music career began writing music for vaudeville acts, then later for Broadway and Hollywood musicals. Some of his most famous songs include Makin' Whoopee! and It Had To Be You. Danny Thomas starred in the 1951 film I'll See You In My Dreams , which was about Kahn.