The influence of manager behaviour on employee positive work behaviour has sought empirical evidence against the backdrop of robust conceptual and theoretical positions on the subject. Considering this debate, this study examines empirical relationship between manager ethical behaviour and employee affective commitment among SMEs operators in Port Harcourt. The study conducted based on positivist philosophy had used the validated and reliable survey instrument to obtain data from a sample of 143 respondents. The data obtained were analyzed using the Pearson Statistic and multiple regression. The co-efficient obtained shows a positive relationship between manager ethical conduct and employee affective commitment. The regression result indicates that up to 68% of the variance in the employee affective commitment construct is predicted by manager ethical behaviour and integrity and accountability components have the highest impact on employee affective commitment. Conclusively, manager ethical behaviour, correlates with employee affective commitment, therefore, it is recommended that manager should show integrity and accountability as a means of attracting commitment through the confidence reposed in managers known for doing the right things