Alyson Michalka, often credited as Aly, is an American actress, singer-songwriter, and musician. Michalka gained a fame for playing the role of Marti Perkins in the CW cheer leading television drama Hellcats. She was also known for her roles as Keely Teslow in the Disney Channel original series Phil of the Future, Charlotte Barnes in the film Bandslam, Taylor Callum in the Disney Channel Original Movie Cow Belles, Rhiannon Abernathy in the Golden Globe-nominated teen film Easy A and as Tracy Morgan in the thriller , "The Roommate". She is also known as one-half of the musical duo 78violet (formerly Aly & AJ) with her sister Amanda Michalka.

She was born in Torrance, California and grew up in Seattle, Washington and Southern California, with her sister, Amanda Michalka. Her father, Mark, owns a contracting company, and her mother, Carrie, is a musician and performed with the Christian "JC Band".

Michalka's acting debut came when she was cast in the role of Keely Teslow on the Disney Channel Original Series, Phil of the Future. She has also starred in the Disney Channel Original Movies Now You See It..., in which she plays Allyson Miller, an ambitious television producer, and Cow Belles, in which she appears opposite her sister. She had a leading role in the Walden Media film Bandslam, about a group of misfits who form a rock band. She co-starred with Vanessa Hudgens and the movie was released in August 2009.

Michalka stars in the CW cheerleading drama series Hellcats, with Ashley Tisdale. The series premiered September 8, 2010. It was announced by the CW that the show will not be renewed for the 2011–12 fall schedule.

Michalka and her sister comprise the musical duo 78violet, and released their first album, Into the Rush, on August 16, 2005. The next year, they brought out a holiday album in September, covering 9 tracks, along with two originals, titled Acoustic Hearts of Winter. In July 2007, their album, Insomniatic, hit stores, featuring the American top 20 hit single, "Potential Breakup Song". The two were to release a third album in early 2010, but it has been postponed after they left their label.