This study addresses the implementation and impact of the Government of Tanzania’s Hospital Management Information System (GoTHOMIS) using a participatory action research (PAR) approach. Its purpose is to assess the implementation factors, strengths and weaknesses of GoTHOMIS on healthcare services in Tanzania. The research employs a PAR methodology involving stakeholders from healthcare facilities, administrators, and I.T. experts. Data collection methods include document evaluation and interviews with key informants. The findings highlight significant areas for improvement in the implementation process, characterized by a top-down approach and a lack of user participation, hindering the system’s successful adoption. Inadequate infrastructure, including network connectivity and outdated hardware, posed further challenges. Compatibility issues with peripheral devices and usability problems were also identified. Despite the challenges, GoTHOMIS demonstrated strengths such as improved accessibility, integration with the MTUHA reporting system, and automation of clinical tasks—weaknesses, including some system components, were only partially automated, which caused inefficiencies in the delivery of healthcare services and failure in integrating with other existing healthcare systems and data sources. Limitations of the study include a focus on selected healthcare facilities, limiting generalizability, and reliance on self-reported data, which may introduce biases. The study’s originality lies in applying a PAR approach to assess GoTHOMIS, providing valuable insights into implementation challenges and potential improvements.