Katherine Grace McNamara (born November 22, 1995) is an American actress, known for playing Clary Fray on the 2016–2019 supernatural drama television series Shadowhunters, and Mia Smoak in the superhero series Arrow. She has also starred as Julie Lawry in the post-apocalyptic miniseries The Stand. Her film roles include Lily Bowman in the 2011 romantic comedy New Year's Eve, Rosa in the 2015 drama A Sort of Homecoming, Sonya in the dystopian science fiction film series Maze Runner, and Amy in the 2021 thriller Trust. McNamara won a Teen Choice Award and a People's Choice Award for her work on Shadowhunters.

Early life and education
McNamara was born in Kansas City, Missouri, the only child of Ursula and Evan McNamara, who served in the U.S. military. She was raised in Lee's Summit, Missouri, and moved to Los Angeles, California in 2011.

While growing up, McNamara was an advanced student in certain subjects, resulting in her being partly homeschooled; she received her high school diploma at age 14. At age 17, McNamara graduated summa cum laude with a Bachelor of Science degree in Business Administration from Drexel University, completing much of her course work online. In July 2017, she said that she was enrolled in an online master's degree literature program at Johns Hopkins University.