Joel Mittleman is an Assistant Professor of Sociology at the University of Pennsylvania, with affiliations in the Population Studies Center and the Program in Gender, Sexuality, and Women’s Studies.

Their research examines inequality in schools and society, with a particular focus on LGBTQ+ populations. Across various projects, they demonstrate how LGBTQ+ populations inspire new ways of conceptualizing gender and innovative approaches to measuring gender inequality. Much of their work advances methods for analyzing inequality beyond the traditional binary categories of female and male.

Their sole-authored research has been published in the American Sociological Review, Demography, Gender & Society, Sociology of Education, Socius, the Journal of Adolescent Health, and Educational Researcher. Their study, "Intersecting the Academic Gender Gap: The Education of Lesbian, Gay, and Bisexual America," received Outstanding Article awards from multiple sections of the American Sociological Association, including Inequality, Poverty & Mobility, Sex & Gender, Sociology of Population, and Sociology of Education, as well as from the Sociology of Education Association. Their op-ed on this study was published in The Washington Post.

With support from the Spencer Foundation and the National Science Foundation, they are currently expanding this research, developing a new, non-binary history of educational stratification across 20th-century America.