AimTo determine the effects of nurses’ trust in first‐line nurse managers on their organizational commitment.BackgroundTrust in managers is known to have important effects on employees’ organizational commitment.MethodsA descriptive, cross‐sectional and correlational research design used in this study. The sample was selected using proportional quota sampling which consisted of 723 nurses working in four hospitals in Istanbul (n = 723). The data collection tools were a nurse information questionnaire, the Trust in Manager Scale and the Organizational Commitment Scale. The data were analysed using descriptive tests, correlation and regression analysis (backward elimination).ResultsThe three regression models which were developed in this study were significant. In these models, the affective commitment subscale had the highest explanatory rate (29.5%). The variables such as being over 40 years old, being employed in a public institution and working on a permanent day shift and the subscales of the trust in manager scale such as support for subordinates and providing a positive work environment were predictors that affected the nurses’ organizational commitment scores positively.ConclusionThe study results show that trust in nurse managers is a determinant of nurse’s organizational commitment.Implications for nursing and health policyFirst‐line nurse managers can increase nurses’ organizational commitments by building their trust with positive and encouraging behaviours. Top managers should point out the role of trust in first‐line nurse managers and indicate the components of trust that lead to positive organizational outcomes.