Employers are constantly seeking to improve employee performance by means of investing in employee training. The results of training are to a large extent dependent on employees’ willingness to behave productively in a cooperative manner. Yet, systematic evidence investigating the causal relation between training and employees’ cooperative behavior is rare. Here we present results from a contextualized laboratory experiment in which subjects, who differ in terms of training participation, were asked to contribute resources to a team effort. We conclude that training promotes cooperative behavior, i.e. voluntary contributions made to the team effort, in teams of employees working together for short periods of time. Training enhances cooperative behavior the most when provided to the higher skilled subjects. We also find that members in more stable teams act very cooperatively under all conditions, but their contributions do not increase further with training.