Cloud computing is used to a greater extent in today’s organizations and enables organizations to obtain on-demand network access to IT services. When cloud computing is adopted in an organization, the IT governance becomes more challenging, because organizations need to address business and IT-related processes as well as managing risks and maintaining the relationship with cloud computing vendors. This research aims at finding how cloud computing service model specifically Software as a Service (SaaS) influence IT governance structures, processes and relational mechanisms in a public organization. For this purpose a case study was conducted in a Swedish municipality and the data was collected through interviews with IT managers and from internal documents of municipality and was analyzed using thematic analysis. The results of this study shows that SaaS influences the IT governance structure by improving roles and responsibilities definition and speeds up the decision-making processes. Moreover, the communication with the vendors is more efficient due to the use of SaaS.