Larisa Romanovna Oleynik (born June 7, 1981) 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 10 Things I Hate About You. Throughout the 2000s, she has mostly appeared in lower-budget films. More recently she made guest appearances on shows like The New Hawaii Five-O & Pretty Little Liars.
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".
While starring as Alex Mack, she parodied the character in an appearance on Nickelodeon's sketch comedy series All That in a sketch called "The Secret World Of Alex Sax". The episode aired on October 21, 1995, and the musical guest was Da Brat. She later appeared as an audience member in the show's 100th episode, helping to provide proper compensation for Lori Beth Denberg to fill in for Danny Tamberelli at the "Vital Information" desk.