Both the newcomer and an important organizational insider, the manager, are predicted to influence the socialization process. Previously, these socialization mechanisms have been discussed or studied in the literature in isolation from one another. Data from 205 newcomers, 364 of their coworkers, and 112 of their managers were used to test the proposed model of newcomer socialization using a longitudinal, 3-wave data collection research design. In general, task-oriented manager behavior predicted task accommodation and relationship-oriented manager behavior predicted relational accommodation. Newcomer proaction, in the form of information seeking, was not a potent predictor of newcomer socialization. Only accommodation variables predicted performance, job satisfaction, and organizational commitment. Thus, it appears that different socialization behaviors tend to serve specialized roles in the socialization process.