Casey Novak is a fictional character on Law & Order: Special Victims Unit, portrayed by Diane Neal. She is the only female Assistant District Attorney (ADA) to have appeared in five complete seasons in any Law & Order series and the third-longest-running ADA in the entire franchise.

Law & Order: Special Victims Unit is an American police procedural crime drama television series created by Dick Wolf for NBC. The first spin-off of Law & Order, it stars Mariska Hargitay as Detective Olivia Benson, now the commanding officer of the Special Victims Unit after originally having been Stabler's partner in a fictionalized version of the New York City Police Department, and Christopher Meloni as Detective Elliot Stabler. Law & Order: Special Victims Unit follows the detectives of the Special Victims Unit as they investigate and prosecute sexually based crimes. Some of the episodes are loosely based on real crimes that have received media attention.