Zachary David Alexander Efron (born October 18, 1987) is an American actor and singer. He began acting in the early 2000s, and became known to young audiences after his roles in the Disney Channel Original Movie High School Musical, the WB series Summerland, and the film version of the Broadway musical Hairspray. Speaking to Newsweek in June 2006, director Adam Shankman described Efron as "arguably the biggest teen star in America right now." In 2007, right before the release of High School Musical 2, Rolling Stone declared him the "poster boy for tweenyboppers" and featured him in their late August issue.

Efron was born in San Luis Obispo, California and later moved to Arroyo Grande, California. His father, David Efron, is an engineer at a power plant, and his mother, Starla Baskett, is a former secretary who worked at the same power plant as Efron's father. Although of Jewish ancestry, Efron was raised agnostic and has never been religious. Efron had a self-described "normal childhood" in a middle class family, and has a younger brother, Dylan. He has said that he would "flip out" if he got a 'B' and not an 'A' in school, and that he was a "class clown." Efron's father encouraged him to begin acting when Efron was eleven. He subsequently appeared in theater productions at his high school, worked in a theater called the Melodrama, and began taking singing lessons. Efron performed in plays such as Gypsy, Peter Pan, Little Shop of Horrors, The Music Man and Mame, appearing at the Pacific Conservatory of the Performing Arts. Efron was recommended to an agent in Los Angeles by his drama teacher, Robyn Metchik (the mother of actors Aaron Michael Metchik and Asher Metchik).

Efron was accepted to the University of Southern California, but deferred his enrollment to Spring 2007 while he works on film projects. He plans to return at some time.

In 2002, Efron began to appear in guest roles on several television series, including Firefly, ER, and The Guardian. He portrayed Cameron Bale on the now-cancelled WB series Summerland. Originally introduced as a recurring character, Efron became a regular cast member on the show in the second season in 2004, starring opposite the likes of Kay Panabaker and Lori Loughlin. Since appearing in Summerland, he has also had guest roles on the shows CSI: Miami, NCIS: Naval Criminal Investigative Service, The Suite Life of Zack & Cody and The Replacements. In 2003, Efron starred in the Lifetime original television movie Miracle Run. He played Steven Morgan, one of two autistic twins. For his performance, he was nominated for a Young Artist Award for Best Performance in a TV Movie, Mini-series or Special - Supporting Young Actor. In 2005, he played a main character in Hope Partlow's music video for her song "Sick Inside." Also in 2005, he played horse-loving Patrick McCardle in The Derby Stallion, where his character wants to beat the town bully at the steeple chase race.

Efron is represented by the Creative Artists Agency.

Efron has two dogs, Australian shepherds named Dreamer and Puppy, along with a Siamese cat named Simon.

Zac is currently involved in a relationship with his High School Musical, High School Musical 2 and High School Musical 3 co-star Vanessa Anne Hudgens.