This article describes the influence of a group-based behavioral intervention for adolescents and young adults newly diagnosed with HIV (Project ACCEPT) on four dimensions of HIV-related stigma-personalized stigma, disclosure concerns, negative self-image, and concern with public attitudes about people with HIV-as measured by the Berger HIV Stigma Scale. Stigma was addressed in a holistic manner during the intervention by providing HIV/AIDS-related information, facilitating the acquisition of coping skills, and providing contact with other youth living with HIV in order to improve social support. Fifty youth (28 male, 22 female; mean age=19.24 years) newly diagnosed with HIV from four geographically diverse clinics participated in a one-group pretest-posttest design study whereby they received the intervention over a 12-week period, and completed assessments at baseline, post-intervention, and 3-month follow-up. Results from the combined sample (males and females) revealed overall reductions in stigma in three dimensions: personalized stigma, disclosure concerns, and negative self-image, although only the combined-sample effects for negative self-image were maintained at 3-month follow-up. Gender-specific analyses revealed that the intervention reduced stigma for males across all four dimensions of stigma, with all effects being maintained to some degree at the 3-month follow-up. Only personalized stigma demonstrated a decrease for females, although this effect was not maintained at the 3-month follow-up; while the other three types of stigma increased at post-intervention and 3-month follow-up. Findings are discussed in terms of gender specific outcomes and the need for a different type of intervention to reduce stigma for young women.