Commitment of employees to their organisations has been one of the central research themes in organisational study. Though, many predictors of organisational commitment abound in the literature, much is however not known on how ethical behaviour in the organisation affects employees' commitment. Considering the nature of insurance services, and high potentials for ethical dilemma in the industry, this study contributes to organisational commitment literature by providing further understanding on the impact of corporate ethical values on organisational commitment in Nigeria. Underpinned by cognitive dissonance theory, the study proposes a significant relationship between the two constructs. While controlling for some demographic factors, corporate ethical values was hypothesized as a significant determinant of organisational commitment. With data from 415 managers, collected through Hunt's et al (1989) Corporate Ethical Value and Hunt's et al (1985) organisational commitment scales, the results of the multivariate analysis were presented, and discussed with managerial implications.