The varying social representations of, and cultural preferences for, body size and their implications for sexual behaviour and risk are necessarily contextual. However, the representational paucity of this literature across developing countries is unfortunate, considering the graver implications of risky sexual behaviour. Thus, we examined the relationship between body size and risky sexual behaviour among sexually active women in a sub-Saharan African country, Ghana. Using the 2014 Ghana Demographic and Health Survey data, we conducted descriptive and ordered logistic regression analyses, differentiated by urban-rural residence, on a weighted sample of 2471 young women between ages 15 and 34. Body size, measured by body mass index (BMI), was categorized as underweight (< 18.5 kg/m 2), normal weight (18.5-24.99 kg/m 2), overweight (≥ 25-29.99 kg/m 2) and obese (≥ 30.0 kg/ m 2). Risky sexual behaviour, measured as no, low and high, was a composite of four self-reported behaviours: early sex, non-condom use, multiple sexual partnership and STI symptoms/diagnosis. Results indicated that compared to normal weight, being overweight, but not obese, was significantly associated with lower odds of risky sexual behaviour. However, older overweight women had a higher likelihood of high risky sexual behaviour compared to normal weight teenagers. These results were identified among the full and urban samples. The study findings suggest that the association between risky sexual behaviour and body size is contextual, and existing relationships among youth require in-depth exploration.