The authors develop a model of grievance initiation that incorporates the grievance-related behaviors of supervisors, employees, and shop stewards, such as the frequency of employee complaints to stewards and the frequency of steward attempts to resolve potential grievances informally. The model is estimated with 1989 survey data on 231 work groups. The grievance-related behavior patterns of the actors are found to be better predictors of grievance rates than the demographic characteristics, attitudes, personality, or other characteristics of employees, stewards, and the workplace, which have been the focus of previous research on grievance initiation.