Gary W. Harper is a Professor in the Department of Psychology at DePaul University in Chicago. Gary is currently the Program Director of the Clinical-Community Psychology Doctoral Training Program, Co-Director of the University's Center for Community and Organization Development, and Co-Chair of the University's DePaul HIV/AIDS Resource Team.

He recently served as chair of the American Psychological Association's Committee on Psychology and AIDS, is currently Chair of the American Psychological Association's Committee on Lesbian, Gay, and Bisexual Concerns. He is also a Fellow in the American Psychological Association; Society for the Psychological Study of Lesbian, Gay and Bisexual Issues; and Society for Community Research and Action.

He has received DePaul University's Excellence in Teaching, Excellence in Public Service awards, and Spirit of DePaul Award; and has been honored by national and state psychological organizations by receiving the Humanitarian Award from the Illinois Psychological Association, the Ethnic Minority Mentorship Award from the Society for Community Research and Action, the Psychology and AIDS Leadership Award from the American Psychological Association, and the Distinguished Contributions to Ethnic Minority Issues by the Society for the Psychological Study of Lesbian, Gay, and Bisexual Issues.

 The focus of Gary's research and social action work is on improving the psychological and physical well-being of various groups of adolescents and young adults who are oppressed and marginalized in our society, including lesbian/gay/bisexual/transgender (LGBT) youth, urban ethnic-minority youth, and youth living with HIV. Although his primary focus has been on examining HIV sexual risk and protective factors among these groups of young people and developing culturally appropriate community-based prevention programs, Gary also addresses other areas of intervention for youth, as well as the formation of community-university partnerships to improve research and service delivery. He recently brought his social action work to Kenya, where he has been developing a peer-to-peer HIV prevention program for youth in rural areas outside of Nairobi.

Gary is also currently conducting a large multi-site study examining the intersection of multiple identities (ethnic, gender, and sexual identities) among gay/bisexual/questioning male adolescents. Gary was the founding chair of the LGBT Interest Group within the Society for Community Research and Action and is the co-editor of a column on LGBT issues in The Community Psychologist. He has co-edited a special issue of The Community Psychologist on LGBT Community Interventions, and also co-edited a special issue of the American Journal of Community Psychology on linking theory, research, and action related to LGBT people and communities. Gary also co-edited a special issue of the journal Cultural Diversity and Ethnic Minority Psychology on lesbian, gay, bisexual, and transgender racial and ethnic minority people and communities. 

Gary also works collaboratively with urban community-basedorganization in Chicago that provide sexual health promotion services and social support programs to gay and bisexual Latino and African-American male adolescents.