Personal initiative is one aspect of contextual performance. Combining the perspective of occupational socialization with the concept of self-efficacy, a general model is proposed and tested that views generalized work-related self-efficacy as an intervening variable in the relation between control and complexity at work and personal initiative. As part of a longitudinal study (N = 463 to 543) in East Germany, two different functions of self-efficacy as an intervening variable were examined: (a) self-efficacy as a mediator and (b) self-efficacy as a moderator. It was found that the relation between control and complexity and concurrent initiative is partly mediated by self-efficacy. In addition, self-efficacy functions as a moderator of the relation between control at work and retrospective initiative. Implications for the general discussion of self-efficacy and contextual performance are suggested.