Abstract Background The aim of this study was to establish the prevalence and risk factors for intergenerational (IG)-sex in females aged 15–19 residing in Barbados. Methods This cross sectional cluster survey was conducted in a 2.6% national sample in the age range (n = 261) recruited from multiple polling districts chosen with a probability proportional to size. Consent was obtained from participants aged ≥18 years or from parents/guardians of participants <18 years, with participant assent. The prevalence of age at first sex was analyzed using a life table approach and risk factors for IG sex (defined as sexual relations with a male 10 or more years older) were analyzed by logistic regression, adjusting for age. Results 51.0% of adolescent females in the survey reported ever having had sex, among whom prevalence of IG-sex was 13.2% (95% CI: 6.7-19.8) at first sex, 29.0% (22.3-35.7) within the preceding twelve months, and 34.8% (24.3-45.4) ever. Condom use at first sex was positively related to willingness to have sex (F statistic = 9.8, p = 0.001). The strongest determinant for IG-sex was age of sexual debut (age adjusted Odds Ratio [95% CI]: 0.58[0.41-0.83]), followed by money or gifts received from the partner (2.91[1.17-7.23] and self-esteem (0.33[0.11-0.95]). Conclusions The survey establishes a high rate of IG-sex in Barbados, a ‘high income’ country. Most insightful is that risk of IG-sex nearly halved for every year at which first sex was delayed. A high proportion of coerced sex was reported at first sexual experience and this was linked to poor condom use. Affirmative prevention approaches are recommended to boost self-acclamation of adolescent women within less coercive relationships, especially during their first sexual encounter.