It's Only a Theory is a British television panel game show, first aired on BBC Four in 2009. It was conceived by and starred Andy Hamilton and featured Reginald D. Hunter as a regular panelist. Announced by the BBC in April 2009, the eight episode series was produced by Hat Trick Productions.

The panelists discuss theories "about life, the universe and everything" submitted by professionals and experts. The panel debates each theory and decides whether it is worth keeping.