Steven Maxwell "Steve" Porcaro (born September 2, 1957, Hartford, Connecticut) is an American keyboardist and composer, who was an original member of the rock band Toto.

Porcaro wrote or co-wrote at least one song on each of Toto's first six albums, with the exception of Isolation. Unlike most of his bandmates, he generally did not contribute lead or even backing vocals; he considered himself a weak singer, and sang lead on two of his compositions only because he felt that the vocal styles of his bandmates, with the exception of Joseph Williams, were not appropriate for his songs. He left Toto in 1986 after the Fahrenheit album in order to pursue a more full-time songwriting and composing career. Porcaro composed the music for the song "Human Nature" from Michael Jackson's album Thriller, and also played with Gary Wright during his tour in 1977, supporting the latter's The Dream Weaver album.