George Grossmith (9 December 1847 – 1 March 1912) was an English comedian, writer, composer, actor, and singer. His performing career spanned more than four decades. As a writer and composer, he created 18 comic operas, nearly 100 musical sketches, some 600 songs and piano pieces, three books and both serious and comic pieces for newspapers and magazines.

Grossmith is best remembered for two aspects of his career. First, he created a series of nine memorable characters in the comic operas of Gilbert and Sullivan from 1877 to 1889, including Sir Joseph Porter, in H.M.S. Pinafore (1878), the Major-General in The Pirates of Penzance (1880) and Ko-Ko in The Mikado (1885–87).

Second, he wrote, in collaboration with his brother Weedon, the 1892 comic novelThe Diary of a Nobody.