"Infected" is the second episode of the fourth season of the post-apocalyptic horror television series The Walking Dead, which aired on AMC on October 20, 2013. The episode was written by Angela Kang and directed by Guy Ferland.

The fourth season of The Walking Dead, an American post-apocalyptic horror television series on AMC, premiered on October 13, 2013, and concluded on March 30, 2014, consisting of 16 episodes. Developed for television by Frank Darabont, the series is based on the eponymous series of comic books by Robert Kirkman, Tony Moore, and Charlie Adlard. It was executive produced by Kirkman, David Alpert, Scott M. Gimple, Greg Nicotero, Tom Luse, and Gale Anne Hurd, with Gimple assuming the role of showrunner after Glen Mazzara's departure from the series. The fourth season was well received by critics. It was nominated for multiple awards and won three, including Best Syndicated/Cable Television Series for the second consecutive year, at the 40th Saturn Awards.