Background An overwhelming proportion of road traffic deaths and injuries in low- and middle-income countries (LMICs) occur in prehospital environments. Lay first responders such as police officers play an important role in providing initial assistance to victims of road traffic injuries either alone or in collaboration with others. The present study evaluated a postcrash first aid (PFA) educational program developed for police officers in Tanzania. Method A 16-hour PFA educational program was conducted in Dar es Salaam, Tanzania, for 135 police officers. Participants completed training surveys before, immediately and six months after the training (before, N = 135; immediately after, N = 135; after six months, N = 102). The primary outcome measures were PFA knowledge, perceived skills confidence, and skills utilization. Parametric and nonparametric tests were used to analyse changes in outcome. Results The mean PFA knowledge score increased from 44.73% before training ( SD = 20.70) to 72.92% six months after training ( SD = 18.12), p ˂ .001, N = 102. The mean PFA perceived skills confidence score (measured on a 1–5 Likert scale) increased from 1.96 before training ( SD = 0.74) to 3.78 six months after training ( SD = 0.70), p ˂ .001, N = 102. Following training, application of the recovery position skill ( n = 42, 46%) and application of the bleeding control skill ( n = 45, 49%) were reported by nearly half of the responding officers. Less than a quarter of officers reported applying head and neck immobilization skills ( n = 20, 22%) following training. Conclusion A PFA educational program has shown to improve police officers’ knowledge and perceived skills confidence on provision of first aid. However qualitative research need to be conducted to shed more light regarding reasons for low utilization of trained first aid skills during follow-up.