INTRODUCTION: This study explored the motivations for and relationship dynamics that may promote girls' vulnerability for intimate partner violence and sources of support reported in unhealthy relationships among girls residing in low-income communities in Ibadan, Nigeria. METHODS: Focus group discussions (n = 14; 122 girls) were conducted among girls aged 15-19 years, who reported having been in a relationship lasting at least 3 months. Girls were recruited from schools and worksites where partner violence has been reported in high proportions. Data were analysed using conceptual content analyses and independently coded by two researchers. RESULTS: Adolescent girls reported keeping their relationships secret from their parents. While girls reported that sometimes relationships were out of love, relationships were also often motivated by girls' financial need. The financial and secretive nature of these relationships appeared to place girls at risk for intimate partner violence, with sexual coercion, resulting in multiple adverse social and health outcomes, including sexually transmitted infections and unintended pregnancy. Girls reported that leaving an abusive relationship is especially difficult when girls rely financially, were sexually involved, pregnant, or have had a child with the male partner. Friends/peers, rather than girls' family, were often the source of support for intimate partner violence. CONCLUSION: Early identification of unhealthy relationships and supporting girls to be financially independent appear to be critical to reduce vulnerability to violence. Peer-based interventions may be most appropriate, given that girls' friends, rather than parents, were most often the source of support for intimate partner violence and other relationship challenges.