In the last decade, research of increasing sophistication has appeared concerning adolescents and young adults who self-identify as lesbian, gay, or bisexual (lgb) (see D'Augelli & Patterson, 2001, for reviews of current research). These youths made their first appearance in the psychological research literature nearly thirty years ago (Roesler & Deisher, 1972), and a non-pathologized conceptual analysis of their life challenges did not appear until the early 1980's (Malyon, 1981). The publication of several papers by Remafedi in 1987 (Remafedi, 1987a, b) launched the contemporary empirical interest in lgb youths. These papers, although based on a small sample of adolescents in Minneapolis, not only focused on their mental health problems, but also attended to the circumstances of their lives, including mistreatment by others because of their sexual orientation. These landmark studies were followed by studies conducted on college campuses (e.g., D'Augelli, 1991) as well as descriptive survey-based studies that included youth from diverse community settings (e.g., D'Augelli & Hershberger, 1993; Savin-Williams, 1990). Several core studies were conducted in urban social service agencies that deal with lgb youths (Herdt & Boxer, 1993; Hunter, 1991). These interview-based studies had the advantage of being able to obtain detailed information unavailable in survey research, but they had the inevitable problem of generalizability. Generalizability to the larger population of youths who have same-sex attractions is a major strength of the population-based surveys that have been the most recent additions to the literature (e.g., Faulkner & Cranston, 1998; Remafedi, Resnick, Blum, & Harris, 1992). These studies use large representative samples of high school students; such studies sort youths by sexual orientation on the basis of questions about same-sex sexual orientation, same-sex sexual behavior, or the gender of youths' sexual partners. These population-based surveys share with other survey research on lgb youths limits on the nature of information obtained; for instance, in some of these studies, only data on sexual behavior are available. Research on lgb youths has endeavored to elucidate the processes of development they undergo as they move through puberty to young adulthood. From the perspective of developmental research, these youths provide information about how sexual orientation evolves prior to puberty and crystallizes thereafter, providing critical insights into how adolescents experience the emergence of sexual identity (Graber & Archibald, 2001; McClintock & Herdt, 1998). In contrast to earlier generations of lgb people who self-identified as non-heterosexual in early adulthood as they established independence from their families of origin, many lgb youths currently self-identify during early adolescence. The earlier timing of contemporary lgb youths' self-identification highlights the importance of the social context on these youths' development (D'Augelli, 1998). These youths are, for the most part, still at home and in school, two crucial social contexts for adolescent development. Thus, they are adolescents whose cognitive, emotional, and social development is still occurring; they are confronting the challenge of disclosing a stigmatized identity; and, their primary social contexts--the home and the school–are often problematic settings. Lgb youths, then, can provide an important population for the study of how social context influences development. Unfortunately, little psychological research on the impact of contextual factors on the development of sexual orientation has occurred (D'Augelli, 1989), despite the crucial role contextual factors have played in the emergence of lgb communities (Garnets & D'Augelli, 1994). This chapter will review research on developmental and contextual factors on the lives of lgb youths. A comprehensive review of the research is beyond the scope of the chapter, and the reader is referred to D'Augelli and Patterson (2001). Instead, this chapter will highlight findings from several studies the author has completed on lgb youths, using the results to demonstrate the importance of employing developmental-contextual thinking in such research.