Only a match between user’s motives and incentives enables an engaging online community. The purpose of this paper is to synthesize the literature on user motivation in online communities into a conceptual framework. The framework categorizes motivational factors along motives and potential incentives and integrates the three major motives need for power, need for achievement and need for affiliation as well as the perspective of outcome- and action-related motivation. Psychological models, which explain motivation as an interrelation between different personal motives and situational incentives, demonstrate that effective incentives have to address matching motives. This paper adds to the existing literature by proposing a conceptual framework, which transfers theory of motivation psychology to the context of engagement in online communities and helps to apply successful incentives.