Jack Halberstam (/ˈhælbərstæm/; born December 15, 1961), also known as Judith Halberstam, is a tenured Professor in the Department of English and Comparative Literature and the Institute for Research on Women, Gender, and Sexuality at Columbia University. Prior to this appointment in 2017, Halberstam was a Professor of American Studies and Ethnicity, Gender Studies, and Comparative Literature and the Director of The Center for Feminist Research at University of Southern California (USC). Halberstam was the Associate Professor in the Department of Literature at the University of California at San Diego before working at USC. Halberstam is a gender and queer theorist and author.