With the growing popularity of Internet communication applications among adolescents, the Internet has become an important social context for their development. This paper examined the relationship between adolescent online activity and well-being. Participants included 156 adolescents between 15 to 18.4 years of age who were surveyed about their access to and use of the Internet. Participants also completed measures of loneliness and perceived social support. An ANOVA suggested that loneliness was not related to the total time spent online, nor to the time spent on e-mail, but was related to participants' gender. Regression analyses suggested that gender and participants' perceptions regarding their online relationships were the only variables that predicted loneliness. Adolescents who felt that their relationship with online partners was one that they could turn to in times of need were more lonely. However, perceived support from significant others was not related to time spent online, time on e-mail, participants' relationships with online partners, and to their perceptions about these relationships. The implications of our results for researchers, parents, and other lay persons are discussed. (Contains 2 tables.)