"He Knows You Know" is a song by the British neo-progressive rock band Marillion. It was their second single, with "Charting the Single" as the B-side. It was released from their first album, Script for a Jester's Tear, and peaked at number 35 on the UK Singles Chart. The song's theme is drug abuse, and alludes particularly to intravenous drug use. In concert, lead vocalist Fish would often introduce it as "The Drug Song" and state that it was inspired by drug use while he was working at the Job/Benefits centre in Aylesbury.