This study examined the self-reported masturbatory experiences of high schoolers and the relationships between masturbation and sexual intercourse and personal characteristics of these young people. A total of 436 suburban Australian adolescents between 15 and 18 years of age participated. Boys were more likely to report ever having masturbated (58.5% versus 42.7%) and to have done so more frequently than girls (38.2% versus 8.7% reporting masturbating three or more times a week). While there was no significant sex difference in the age of initiation of masturbation, there was some evidence that girls began masturbation earlier than boys. Whether sexual intercourse replaced or supplemented masturbation as a sexual practice could not be resolved, but there was evidence that masturbation was positively correlated with sexual self-esteem. Young people whose parents provided a more open environment for the discussion of sexuality were more likely to report having masturbated, although the environment had a complex relationship with masturbatory practices as did young people's self-rated physical maturity compared to their peers. A range of social and contextual factors must be explored to understand more fully this important component of young people's sexual experience.