Sarah Louise Christine Chalke (born August 27, 1976) is a Canadian actress and model. She is best known for her roles as Kate Mularkey on Netflix's Firefly Lane, Gabi in the movie Mother's Day, Paula Crowe in Chaos Theory, Dr. Elliot Reid on the NBC/ABC sitcom Scrubs, Gloria Macintosh in the movie Nothing Too Good for a Cowboy and on the subsequent CBC series, Muriel Jake's on Showtime's series Dead Man's Gun, Annie on CTV's series Neon Rider, and "Second Becky" Conner on Roseanne.

She's had recurring roles as Merrill Morgan on Netflix's Friends from College, Melanie Hertzal on ABC's sitcom Speechless, Amy Gazanian on FOX's series Backstrom, and Stella Zinman on CBS's sitcom How I Met Your Mother.