Background There is growing concern towards ensuring that patients are safe. Despite this, factors influencing safety practices and outcomes in healthcare delivery systems in Nigeria have not been determined exhaustively. Objective To determine the factors affecting patient safety culture (PSC) practices in a tertiary hospital in Nigeria. Materials and methods This cross-sectional descriptive study of care providers in a tertiary hospital in Nigeria was conducted from June to November, 2016. A self-administered structured questionnaire survey (QS) was used to assess PSC via 12 composites. Data were analysed using Statistical Package for Social Sciences version 22 and associations tested with Chi-square at p ≤ 0.05. Results Response rate is 87%, with a validity rate of 88%. Supervisor/manager expectations and actions promoting safety has the highest positive response of 70.7%, while Non-punitive response to error has the least, 43.1%. The overall PSC grade level is 62.3%. The knowledge of PSC is 54.5%, 54% never reports safety events. Knowledge of PSOP, Knowledge of the availability of PSU, Report of errors and Regular patient safety committee meetings (PSCM) influences the scores on four, three, two and seven PSC composite units ( p < 0.05 respectively). Conclusions This study finds an apparently fair overall PSC grade level. Knowledge of PSOP and availability of PSC unit, reports errors and regular PSCM positively influences PSC. There is need for composite targeted cum overall improvement on PSC in the setting.