Matthew Michael Carnahan (sometimes credited as Matt Carnahan) is an American screenwriter who wrote the feature film The Kingdom (2007), and the film adaptation of the hit BBC television drama serial State of Play. Carnahan also wrote the screenplay for Lions for Lambs for United Artists. His brother is Joe Carnahan, who wrote and directed Narc (2002), Smokin' Aces (2006) and The A-Team (2010).
More recently, he worked on the screenplay for the zombie film World War Z (2013). He wrote the screenplay for the film adaptation of Nemesis with his brother Joe Carnahan.
- The Kingdom (2007) - Writer
- Lions for Lambs (2007) - Writer/Producer
- State of Play (2009) - Writer
- World War Z (2013) - Writer
- Deepwater Horizon (2016) - Writer
- Codes of Conduct (2015) - Co-creator and co-Writer (with Steve McQueen)