BACKGROUND More than one-third of women in the U.S. have engaged in heterosexual anal intercourse (HAI), but little is known regarding women's perceptions of HAI and motivations for engaging in this sexual behavior. OBJECTIVE This study aimed to explore U.S. women's motivations for engaging in HAI and to investigate how they navigate HAI in the context of sexual relationships. METHODS Semi-structured interviews were conducted with 20 women, ages 18-50 years old, who had engaged in anal intercourse with a male partner within the past 3 months. The interview guide was developed utilizing a conceptual framework based on the Theory of Planned Behavior. METHODS Thematic content analysis was performed, and salient themes were identified. RESULTS Salient themes were identified in all key components of the construct, including attitudes toward the behavior, subjective norms, and perceived behavioral control. Women's intent to engage in HAI was influenced by their attitudes toward HAI and level of control and trust with their partners. Primary motivators were partner and personal pleasure and sexual curiosity and experimentation. CONCLUSIONS The Theory of Planned Behavior construct was well suited to explore factors influencing women's intent to engage in HAI. Most women perceive negative societal norms toward HAI. Although this does not appear to affect intention to engage in HAI, it does affect disclosure of this sexual activity with friends and healthcare providers. It is important for healthcare providers to provide open, non-judgmental counseling regarding HAI to decrease stigma, enhance communication, and improve sexual health. Benson LS, Gilmore KC, Micks EA, et al. Perceptions of Anal Intercourse Among Heterosexual Women: A Pilot Qualitative Study. Sex Med 2019;7:198-206.