Corporate social responsibility (CSR) plays an important role in promoting workplace ethics. However, most research has focused on CSRs’ performance or favourable performance-related behaviour outcomes. Little is known about how individual employees perceive CSR and how this affects their ethical behaviour. This research examines how employees' perceived corporate social responsibility (PCSR) facilitates their ethical behaviour. Specifically, we hypothesise that PCSR influences employee ethical behaviour by enhancing employees' organisational commitment. The relationship between employees' commitment and ethical behaviour is contingent on their co-workers' ethical behaviour. The hypothesised relationships were assessed using partial least squares structural equation modelling with a sample of 300 employees from ‘The Ghana Club 100’ firms. Our findings suggest that employee commitment serves as an effective mechanism through which employees' perception enhances their ethical behaviour. The findings also show that the weaker the co-workers' ethical behaviour, the stronger the relationship between employee commitment and ethical behaviour. Both theoretical and practical implications are discussed.