BACKGROUND: Pre-exposure prophylaxis (PrEP) delivery to adolescent girls and young women (AGYW) is scaling up in sub-Saharan African countries. Understanding how AGYW learn about PrEP is needed to inform programs seeking to reach AGYW with HIV prevention tools. METHODS: AGYW (ages 15-24), attending routine family planning and maternal child health clinics in Kisumu, Kenya, participated in in-depth interviews. AGYW were recruited if they either declined or accepted PrEP when offered that day in clinic or were currently or previously on PrEP. Thematic analysis was used to identify key themes related to the type and quality of knowledge sources from which AGYW first became aware of PrEP. RESULTS: Overall, 140 in-depth interviews were conducted with AGYW. The median age was 21.5 years (interquartile range: 20.0-23.0), 65% of participants were married, and almost half (45.7%) were currently taking PrEP. Participants reported learning about PrEP from 3 primary sources: (1) clinic-based education; (2) friends, family, or other PrEP users; and (3) media and community outreach. Participants who reported learning about PrEP from friends or family were highly enthusiastic about PrEP. The accuracy and completeness of knowledge varied with most inaccuracies around the cost, dosing, and who benefits from PrEP. Community outreach campaigns provided fewer details, resulting in more inaccurate information and distrust of information received. CONCLUSION: PrEP information reaches AGYW through many sources with variable accuracy and completeness. Training providers and peer leaders to disseminate thorough and accurate PrEP information when counseling AGYW could positively impact acceptance and proper use.