The capability to collaborate successfully within and between organizational units using online media supports organizations in addressing the increasing complexity of work tasks of knowledge workers. However, organizations are struggling to develop and sustain their intraorganizational online collaboration (IOC) capabilities organization-wide. Hence, holistic approaches to effectively manage this capability are needed. This paper addresses this problem by introducing a maturity model for intraorganizational online collaboration. The model builds on related maturity models and research of the domain. In a four-round ranking-type Delphi study, essential capability areas for IOC were identified and refined, and a general maturation path was developed. Compared to related maturity models, the presented maturity model addresses the specific domain focus of online collaboration within an organization from an organization-wide perspective. The model provides a framework for design elements for intraorganizational online collaboration and a highly reliable general maturation path.