Today, retention of valuable employees is a global challenge faced by organizations and executives that is particularly pronounced in the information technology industry, due to sudden increase of the global demand for IT services providers. Therefore, the main goal of this research was to investigate the relationship between a multidimensional, theoretically grounded configuration of high-involvement human resources practices and turnover intentions among employees in the IT sector and the mediating effect of organizational commitment on this relationship. The online research, completed by 107 employees of the IT department in one organization, included a questionnaire on general and sociodemographic data, scales measuring High-involvement Human Resources Management Practices, Organizational Commitment Scale, Organizational Citizenship Behavior Scale, and Turnover Intentions Scale. Obtained results show that perceived levels of high-involvement human resources management practices are significantly positively correlated with affective organizational commitment and negatively with turnover intentions. These practices have not been shown significantly correlated with instrumental organizational commitment, nor organizational citizenship behavior. Furthermore, turnover intentions were most, compared to other variables, negatively correlated with affective and instrumental organizational commitment, while a significant correlation with the originally mentioned variable and organizational citizenship behavior was not found. Results of hierarchical regression analysis show that high-involvement human resources management practices and affective and instrumental organizational commitment all have a unique independent contribution in explaining the variance of turnover intentions, while organizational citizenship behavior proved to be a suppressor variable. Finally, neither affective nor instrumental organizational commitment had a significant mediating effect on the relationship between the perceived levels of high-involvement human resources management practices and turnover intentions.