Truck drivers are part of mobile populations which have been noted as a key population at risk of HIV in Zambia. This study was aimed at: (1) determining potentially traumatic events (PTEs), labour migrant-related stressors, psychosocial problems and HIV risk behaviours among truck drivers in Zambia; and (2) examining the relationship between PTEs, migrant-related stressors, psychosocial outcomes and HIV sexual risk behaviour among truck drivers in Zambia. We conducted 15 semi-structured interviews with purposively sampled male truck drivers at trucking companies in Lusaka, Zambia. Findings indicate that truck drivers experience multiple stressors and potentially traumatic incidences, including delays and long waiting hours at borders, exposure to crime and violence, poverty, stress related to resisting temptation of sexual interactions with sex workers or migrant women, and job-related safety concerns. Multiple psychosocial problems such as intimate partner violence, loneliness, anxiety and depression-like symptoms were noted. Transactional sex, coupled with inconsistent condom use, were identified as HIV sexual risk behaviours. Findings suggest the critical need to develop HIV-prevention interventions which account for mobility, potentially traumatic events, psychosocial problems, and the extreme fear of HIV testing among this key population.