The mutual-investment model predicts a positive relation between investments in training and employees' willingness to behave cooperatively. In this paper, we argue that the extent to which employees increase their cooperative behavior after receiving training depends on the type of training provided, the skillfulness of the employee and the cohesiveness of the team. Focusing on intentions to help coworkers as an indicator for cooperative behavior, we conducted a vignette experiment among 2388 employees working in 127 organizations from four European countries. Multilevel analyses show that training increases employees' intentions to help coworkers. Training promotes helping intentions the most when organizations provide general instead of firm-specific training and when given to employees with limited skills. Whereas employees in cohesive teams indicate higher intentions to help coworkers than employees in non-cohesive teams, training promotes helping intentions equally in both types of teams.