Kunis was born in Kiev, Ukrainian SSR (now Ukraine), to a Jewish family, with whom she moved to Los Angeles, California, in the United States, when she was seven. Kunis learned English by watching The Price Is Right; host Bob Barker spoke slowly enough for her to understand. In Los Angeles, where she attended Hubert Howe Bancroft Middle School, Kunis took after-school acting classes and was cast in minor roles in children's programs and television commercials, appearing in a 1994 episode of Days of Our Lives as a young Hope Williams.

Kunis became well known after being cast in the television series That '70s Show, in 1998. She told them that she was going to be 17, not specifying when at the audition: although the character was supposed to be 16, she was actually 14. Kunis has stated many times that she is nothing like Jackie, her character on the show, insisting that she is really more of the cute girl-next-door type with a dash of tomboy thrown in for good measure. But before this she was in the 1997 film Honey, We Shrunk Ourselves as a minor character (the daughter's friend). Despite this docile description, she has shown a different attitude by her sultry appearance on the cover of the men's magazine Stuff in December of 2005. Maxim magazine named her #47 on its 2006 Hot 100 list.

Kunis's inimitable, instantly recognizable voice has earned her several other notable roles, including starring in the Aerosmith music video "Jaded", The Strokes music video "The End Has No End", as well as several movies, such as Piranha (1995), Santa with Muscles (1996), Krippendorf's Tribe (1998), Gia (1998), Get Over It (2001), American Psycho II: All American Girl (2002), and Tony n' Tina's Wedding (2004). She is starring with Jon Heder in the upcoming film Moving McAllister.

Kunis can also be heard as the voice of Meg Griffin in the animated TV show Family Guy, and of several characters on the Adult Swim show Robot Chicken. She is also lent her voice to Tanya Winters in the video game Saints Row.