The second series of the British police procedural television programme Line of Duty was broadcast on BBC Two between 12 February and 19 March 2014.

AC-12 is led by Superintendent Ted Hastings (Adrian Dunbar), who is assisted by his team DS Steve Arnott (Martin Compston), DC Kate Fleming (Vicky McClure), and DI Matthew "Dot" Cottan (Craig Parkinson).

Supporting characters include DCC Mike Dryden (Mark Bonnar), Jo Dwyer (Liz White), DCS Lester Hargreaves (Tony Pitts), DC Nigel Morton (Neil Morrissey), and Tommy Hunter (Brian McCardie).

Dryden receives a suspended sentence for perverting the course of justice for the driving offence and resigns from the police force.

[5][6] Creator Jed Mercurio wrote the series's episodes and executive produced it alongside Simon Heath for World Productions and Stephen Wright for BBC Northern Ireland.

[12] Lindsay departed from the series after two days of filming due to "creative differences" and was later replaced by Mark Bonnar.

[23] The series was first broadcast in the United Kingdom on BBC Two beginning 12 February 2014 and concluding six weeks later on 19 March.

[48] Yvonne Roberts from The Guardian also admired the performance of Hawes, writing that the series "smash[ed] gender stereotypes".

[51] Alex Fletcher, writing for Digital Spy, commended Mercurio's scripts for ending the series on a less-than satisfying resolution.

[54] Euan Ferguson later ranked the series number one on The Guardian's "Best British TV dramas of 2014" list.