The present thesis analyzes factors, which influence knowledge sharing through enterprise social software. Subsequent to a comprehensive literature review as well as a theoretical (economic and socio-psychological) discussion, determinants of knowledge sharing through enterprise social software are identified. On the one hand, first empirical evidence for the identified factors were demonstrated by the qualitative analyses (interviews/meta-analysis of case studies) and, on the other hand, three additional determinants were detected. The self-compiled data (1268 data sets) are empirically investigated by using a structural equation modelling technique. A major contribution of the thesis lies in the identification of influential factors, such as “effort expectancy”, “performance expectancy”, “facilitating conditions”, “trust in technology”, “personal innovativeness”, “social rewards for knowledge sharing” as well as moderation factors, such as “self-efficacy”, “norms of knowledge sharing”, “management support”, “age”, and “experience with public social software”. In addition, the relevance of the factors, differentiated according to implementation stages (pre-implementation stage and post-implementation stage), is exposed. Not only should the results enable organizations to anticipate potential success factors in order to take tailor-made solutions into account, but they should also prevent organizations from implementing ineffective measures.