Abstract Background A country will trust, value, and use, its health information system (HIS) to the extent it has had a role in its creation and maintenance. A sense of ownership contributes in turn to the long-term sustainability of the HIS, and thus the country’s ability to monitor and evaluate population health and health services. To facilitate progress toward greater ownership, we developed and tested a tool to measure the country’s ownership of its monitoring and evaluation (M&E) system. Methods Through a systematic review of the literature, we identified four dimensions of country ownership of an M&E system: partnership, commitment and responsibility, capacity, and accountability. We identified relevant indicators of the dimensions already in use in other tools used to assess M&E systems. We tested the data collection tool with 95 stakeholders of the Tanzanian HIS for HIV/AIDS control. Results We identified 56 items that addressed elements of the four dimensions. The respondents found our tool for assessing country ownership of an HIS to be clear and relevant, leading to the identification of important issues to be discussed. For example, all stakeholder groups affirmed that the Tanzanian Commission for AIDS is “playing a leadership role in addressing HIV through collaborative partnerships and work across borders to achieve greater impact.” While many respondents disagreed with the statement, “There is an adequate number of government monitoring and evaluation posts at the sub-national level.” Conclusions Stakeholders found the M&E country ownership tool to address relevant questions clearly. It enabled them to identify successes and challenges within four dimensions of country ownership. It thus holds the potential to lead to an agenda for strengthening country ownership. If implemented every few years, the tool can provide a means of monitoring progress through a set of standardized indicators. As country ownership of M&E increases, so will the long-term sustainability of the HIS.