Margaret Cassidy "Maggie" Lawson (born August 12, 1980) is an American actress who is best known for her role as Detective Juliet "Jules" O'Hara in the TV show Psych. She also has starred in the sitcoms Inside Schwartz, It's All Relative, and Crumbs, as well as the television movie Nancy Drew. In late 2014 and early 2015, she had a supporting role as Miss McMartin in the 12th and final season of Two and a Half Men.
Lawson was born in Louisville, Kentucky, the daughter of Judy, a homemaker, and Mike Lawson, a hotel manager. She attended Assumption High School, an all-girls Catholic school. Early on, she co-hosted WDRB Fox 41 Kid's Club in Louisville. In 2000, she starred in Model Behavior, a Disney Channel movie featuring Justin Timberlake. She also made guest appearances on television series such as Smallville and Fear Itself.
She co-starred in the USA Network original series, Psych, as Detective Juliet O'Hara. Lawson dated Psych co-star James Roday for eight years; the show ended its run in 2014.