"What Is This Thing Called Love?" is a 1929 popular song written by Cole Porter, for the musical Wake Up and Dream. It was first performed by Elsie Carlisle in March 1929. The song has become a popular jazz standard and one of Porter's most often played compositions.

Wake Up and Dream ran for 263 shows in London. The show was also noticed in New York, and the critics praised Tilly Losch's performance of the song. The show was produced on Broadway in December 1929; in the American rendition, "What Is This Thing Called Love" was sung by Frances Shelley. Ginny Simms performed the song in the 1946 biographical film about Porter's life, Night and Day.

Jazz musicians soon included the song in their repertoire. The recordings of Ben Bernie and Fred Rich made it to the charts in 1930, and the song was also recorded by stride pianist James P. Johnson, clarinetist Artie Shaw and guitarist Les Paul. The piece is usually performed at a fast tempo; the 1956 recording of Clifford Brown and Max Roach with Sonny Rollins is one of the best-known uptempo instrumental versions. Saxophonist Sidney Bechet made a slow rendition in 1941 with Charlie Shavers.