Drawing on a social cognitive theory perspective, we contend that an employee's trust in oneself, or self‐efficacy, will interact with the individual's trust in the system, or trust in organization, to predict job attitudes and behaviours. Specifically, we expected that self‐efficacy would have stronger effects on job attitudes (job satisfaction and turnover intentions) and behaviours (task performance and organizational citizenship behaviours) to the degree to which employees perceive high levels of trust in organization. Using data collected from 300 employees and their respective supervisors at a manufacturing organization in Turkey across three waves, we found that self‐efficacy had more positive effects on job satisfaction, task performance, and citizenship behaviours when trust in organization was high. Interestingly, self‐efficacy had a positive effect on turnover intentions when trust in organization was low, indicating that high trust in organization buffered the effects of self‐efficacy on intentions to leave. The results suggest that the motivational value of trust in oneself is stronger to the degree to which employees also have high trust in the system, whereas low trust in system neutralizes the motivational benefits of self‐efficacy.