The implementation and development of online collaborative working methods within companies, project teams, and departments can support creating and distributing knowledge to accomplish common business goals. The current scientific literature reveals a lack of condensed knowledge, which causes uncertainty regarding what to focus on and which obstacles to avoid while establishing, maintaining and improving intra-organisational online collaboration (IOC). The aim of this research is to create a systematisation of literature, which gives a complete and structured overview of success factors for IOC. Therefore, an extensive systematic literature review was conducted. Additional expert interviews allowed in-depth descriptions and ensured a practical perspective. Both literature and interviews are systematically analysed using qualitative content analysis. The result is a systematisation of 32 success factors of IOC, which are categorised in collaborative human, collaborative organisation and collaborative technology. This gives an overview of adjustment factors, to establish, maintain and improve IOC.