Organisational Culture exerts a significant influence on how employees of an organisation think and act. Culture has been found to associate directly as well as indirectly with Organisational Citizenship Behaviour, which has often been considered as one of the indices of organisational effectiveness and performance. Literature suggests that certain kinds of organisational culture promote organisational citizenship behaviour (OCB). Also, organisational commitment has exhibited a positive influence on extra-role behavior like OCB. The purpose of this paper was precisely to investigate the relationship between organisational culture values (Openness, Confrontation, Trust, Authenticity, Proaction, Autonomy, Collaboration & Experimentation) and organizational commitment with OCB. A survey method was used for collecting data from 295 participants, who belonged to private and public sectors of three different types of organisations, namely, banks, construction companies and schools. OCTAPACE Profile by Pareek and Rao (1992) was used to assess organisational culture. Organizational commitment was measured using a scale by Mayer et al. (1993) with three types of commitment- affective, normative and continuance. Organisational citizenship behaviour scale, comprising four dimensions- Helping, Initiating, Defending and Refraining was developed by the researcher. Correlation, regression and mediation analysis were performed. The findings pointed out that OCTAPACE values as well as types of commitment could predict OCB dimensions with large variances in them in most of the organisations. It means OCTAPACE values perceived by employees and commitment of the employees towards their organisation will lead them to engage in OCB. However, certain specific relationships between the constructs were negative or non-significant. Findings were interpreted and their implications and limitations were discussed.