"St. Jimmy" is the sixth track on Green Day's 2004 rock opera American Idiot. The song's title refers to the character of St. Jimmy, who features prominently throughout the album.

"St. Jimmy" is often combined with the song "Are We the Waiting", the preceding song on American Idiot and between which there is no pause in the music. Beginning in the same key (A) as the "Are We the Waiting", "St. Jimmy" has a brisk tempo of 136 BPM. Following the intro, and a count of "1, 2, 1, 2, 3, 4", the song continues in double time.