Larisa Romanovna Oleynik is an American actress. She came to fame in the mid 1990s, after starring in the title role of the popular television series, The Secret World of Alex Mack, and has also appeared in theatrical films, including The Baby-Sitters Club and 1999's 10 Things I Hate about You. Throughout the 2000s, she has mostly appeared in lower-budget films.

During her period as a teen idol, Oleynik was described as "one of America's favorite 15-year-olds" and "the proverbial girl next door".