Abstract: Organizational commitment is the key to increase organizational performance with the ultimate purpose of achieving its goals and objectives. The current study was aimed at investigating the impact of Psychological capital on organizational commitment of staff employees of a sugar manufacturing company in Sri Lanka. Since Staff employees were selected as the population and population size is 81. The sample size of the study was 66 and convenience sampling method was followed. Data were collected through standard questionnaires and a multiple regression was performed to investigate the impacts of the variables interested. Organizational commitment acted as the dependent variable where self-efficacy, optimism, hope and resilience were the predictors of the study. The current study brought evidence to a significant positive impact of optimism, hope and resilience on organizational commitment and no any impact of self-efficacy on organizational commitment.