Murphy's Law is a BBC television drama, produced by Tiger Aspect Productions for BBC Northern Ireland, starring James Nesbitt as undercover police officer Tommy Murphy. There were five series of the drama, shown on BBC One. The first two were composed of individual stories. Series three, four and five were each single stories composed over multiple episodes. Colin Bateman adapted the pilot for a novel.

A sixth series has not been commissioned. In a 2008 interview, Nesbitt attributed this to the fifth series' ratings being damaged after it was scheduled opposite ITV's popular drama Doc Martin.

All 23 episodes have since been released on DVD. All episodes from series two onwards were released as edited 50-minute masters instead of the 60-minute versions that were broadcast, except series 3 which was released uncut in the US. The first, second and third series were all released on 28 August 2006. The fourth and fifth series were released in a joint box-set on 15 October 2007.