"Mansize Rooster" is a song by English rock band Supergrass, released as the second single from their debut album, I Should Coco (1995). It reached number 20 on the UK Singles Chart, remaining on the chart for three weeks.

Supergrass are an English rock band formed in 1993 in Oxford. For the majority of the band's tenure, the line-up consisted of brothers Gaz and Rob Coombes (keyboards), Mick Quinn and Danny Goffey. Originally a three-piece, the band was officially joined by Rob Coombes in 2002.