Prevalence, frequency, and psychosocial predictors of Internet and computer game use were assessed with 803 male and 788 female adolescents across 2 time periods, 21 months apart. At Time 1, participants were in the 9th or 10th grade; at Time 2, they were in the 11th or 12th grade. Most girls (93.7%) and boys (94.7%) reported using the Internet at both time periods, whereas more boys (80.3%) than girls (28.8%) reported gaming at both time periods. Girls reported a small decrease over time in the frequency of hours spent per day on overall technology use, mostly due to a decrease in gaming. Both linear and curvilinear relations were examined between parental relationships, friendship quality, academic orientation, and well-being measured in early high school and the frequency of technology use in late high school. Being male significantly predicted both computer gaming and Internet use. There also were trends in favor of higher friendship quality and less positive parental relationships predicting higher frequency of Internet use. Importantly, moderate use of the Internet was associated with a more positive academic orientation than nonuse or high levels of use.