Purpose – The purpose of this paper is to investigate whether there was a relationship between commitment and the behaviour of organizational citizenship among bank employees. Design/methodology/approach – This paper is based on the outcomes of a doctoral dissertation, which was a case study combining a mix methodology. The results validated the conceptual model proposed by the researcher and answered the research questions. Measurement instruments used include the organizational citizenship scale and the organizational commitment scale, developed and validated by Rosario et al. (2004). Findings – The paper finds that there is a positive correlation between the organizational commitment and the indicators of organizational citizenship behaviour and civic virtue, courtesy and altruism dimensions shown by the employees. The dimensions of affective and moral commitment had the strongest correlation with the civic virtue dimension of organizational citizenship. Research limitations/implications – Sample consist only of private banking employees. Practical implications – The organizations should support the affective and moral commitment in their personnel in order to develop strong citizenship behaviour. Social implications – The organizational commitment with demonstrations of citizenship behaviour, civic virtue, and courtesy and altruism dimensions may impact the organization and the community creating a good base to improve the quality of life. Originality/value – This is the first attempt to study the relationship between organizational commitments and organizational citizenship behaviour in a sample of private banking employees in Puerto Rico.