Gabrielle Monique Union (born October 29, 1972) is an American actress, voice artist, activist, and author. She began her career in the 1990s, appearing on television sitcoms, before landing supporting roles in teenage comedy films She's All That and 10 Things I Hate About You (1999). Her breakthrough role was in the 2000 film Bring It On.

Union is known for her performances in the romantic comedy films The Brothers (2001), Deliver Us from Eva (2003), Daddy's Little Girls (2007), Think Like a Man (2012) and Think Like a Man Too (2014). She also had starring roles in the CBS medical drama series City of Angels (2000) and films Bad Boys II (2003), Cradle 2 the Grave (2003), Neo Ned (2005), Cadillac Records (2008), Top Five (2014) and Breaking In (2018). In 2013, Union began starring as lead character in the BET drama series Being Mary Jane, for which she has received an NAACP Image Award. She co-starred in the 2016 film The Birth of a Nation, and next appeared in Almost Christmas (2016) and Sleepless (2017).

Outside of acting, Union has written three books: a memoir, entitled We're Going to Need More Wine (2017), and two children's books, entitled Welcome to the Party (2020) and Shady Baby (2021). She has also been an outspoken advocate for issues involving women's health and violence against women. Union was included on Time's list of the 100 most influential people in the world in 2020.