This study tested with Gabonese employees (N = 146) an organizational citizenship behavior (OCB) model based on the motivational model of job burnout (MMJB). It was hypothesized that the more supervisors will satisfy employee's needs for self-determination, competence, and relatedness, the more employee work motivations will be self-determined. Supervisory style and motivation will then predict job satisfaction which then influences life satisfaction. Work motivation and job satisfaction should also determine OCB and the latter should then influence life satisfaction. Structural equation modeling analyses mostly confirmed the model. One unexpected link was that altruism OCB was negatively predicted by self-determined motivations which then negatively predicted life satisfaction. Results support SDT showing, as such, that a behavior regulated by non-self-determined motivations will negatively affect well-being.