Background: Sexuality studies have often overlooked ethnic and cultural differences affecting parentteen sex conversations and the potential implications for Black teens’ sexual activity. Purpose: Examine the relationship between parent-teen sex conversations and teens’ sexual activity among ethnically diverse Black adolescents in Miami, Florida. Methods: Using cross-sectional survey methodology, 157 Black adolescents specifically, African Americans, Haitians, and Jamaicans (ages 14-18 years) were recruited through community-serving organizations and schools in Miami, Florida to complete a 52-item questionnaire. Regression analysis was used to determine the relationship between parent-teen sex conversations and teens’ sexual activity. Results: Teens’ mean age was 16 years, (SD=1.49), 60% were female. Fifty percent of African Americans, 39% of Haitians, and 34% of Jamaicans were sexually active. Age of penile-vaginal/anal sexual debut was 14.15 years (SD=1.51) for Jamaicans, 15.09 years (SD=1.94) for African Americans, and 15.38 years, (SD=1.56) for Haitians. Of the three groups, Haitians reported lower comfort and value for family-sex conversations. Cultural differences affected families’ engagement in sex conversations, however teens benefited from parents’ messages on delaying sex and safer-sex practices. Conclusion: Findings call for culturally-appropriate public health interventions to improve families’ comfort and communication skills for sex conversations particularly in communities where these conversations contradict cultural norms.