This paper explores barriers to consistent condom use among female sex workers in Jamaica in a qualitative study using grounded theory. Multiple perspectives were sought through 44 in-depth interviews conducted with female sex workers, clients, the partners of sex workers and facilitators of sex work. Poverty and lack of education or skills, severely limited support systems as well as childhood abuse served to push the majority of participants into sex work and created vulnerability to HIV and other STIs. Despite these constraints, women found ways to exercise agency, ensure condom use, adopt protective measures and gain economic advantage in various aspects of the Jamaican sex trade. Perceived relationship intimacy between sex workers and their clients and/or their main partners emerged as the main factor contributing to reduced risk perception and inconsistent condom use. Relationship intimacy, with associated trust and affirmation of self, is the most important factor influencing sexual decision-making with respect to lapse in condom use among female sex workers in Jamaica. Study findings provide important insights that can enhance individual psychosocial, interpersonal and community-based interventions as well as inform environmental, structural and policy interventions to reduce risk and vulnerability among female sex workers.