Burnt Weeny Sandwich is the seventh album by the American rock band the Mothers of Invention, and the ninth overall by Frank Zappa, released in 1970. It consists of both studio and live recordings. Following the Mothers' split in late 1969, Zappa assembled two albums of unreleased recordings by the band - this album and its follow-up Weasels Ripped My Flesh. Burnt Weeny Sandwich focuses mostly on studio recordings and tightly arranged compositions, while Weasels Ripped My Flesh focuses mostly on live recordings and loose/improvisational pieces. Both albums also include some outtakes/leftovers from the sessions for Zappa's 1969 solo album Hot Rats.
The LP included a large triple-folded black and white poster ("The Mothers of Invention Sincerely Regret to Inform You") which has never been reproduced in any of the CD reissues (except the Japanese Ryko mini-lp sleeve editions).