Alexandrea Borstein (born February 15, 1971 or 1973) is an American actress, writer, producer, and comedian. She is known for voicing Lois Griffin on the animated television series Family Guy, and has had lead roles as Dawn Forchette in the medical comedy series Getting On, Susie Myerson in the historical comedy-drama series The Marvelous Mrs. Maisel, and as various characters on the sketch comedy series MADtv. Borstein has held supporting roles in films including The Lizzie McGuire Movie (2003), Catwoman (2004), Ted (2012), ParaNorman (2012), A Million Ways to Die in the West (2014), and The Angry Birds Movie (2016).

A native of Deerfield, Illinois, Borstein is a graduate of San Francisco State University, where she studied rhetoric. She was trained in improvisational comedy at the ACME Comedy Theatre, near Hollywood, California, and was selected to join MADtv after being scouted by talent agents who noticed her work at the theatre. She was a writer and voice actor for several television shows, including Casper, Pinky and the Brain, and Power Rangers: Zeo, before joining the cast of MADtv in 1997 as a featured player, becoming a repertory player mid-season.