Janet Mock was born in Honolulu, Hawaii, the second child in the family. Her father, Charlie Mock III, is African-American, and her mother, Elizabeth (née Barrett), is of half native Hawaiian descent and half European descent. Mock lived for most of her youth in her native Hawaii, with a portion in Oakland, California and Dallas. She began her transition from male to female as a freshman in high school, and funded her medical transition by earning money as a sex worker in her teens. She played volleyball in high school, a sport she had bonded over with her childhood friend Wendi, who helped Janet express her femininity. She chose her name Janet after Janet Jackson. She was the first person in her family to go to college. She underwent sex reassignment surgery in Thailand at the age of 18 in the middle of her first year in college. Mock earned a Bachelor of Arts in Fashion Merchandising from the University of Hawaii at Manoa in 2004 and a Master of Arts in Journalism from New York University in 2006.