Globally, the population living in urban areas is increasing with a strong impact on land use patterns, particularly on the availability and use of green spaces. The impact of green spaces is beneficial to health, for example, by reducing mortality or improving mental health. These effects are also related to different ecosystem services provided by green spaces, such as regulating temperature, modifying air pollution and noise levels, and offering more opportunities for physical activity. GreenUr is a plugin for QGIS that aims at putting together knowledge and information on the impacts of green space on health. It is developed as a prototype representing a work in progress coordinated by the World Health Organization (WHO) to provide an educational tool to introduce the relation between green spaces, health, and well-being and raise awareness of the importance of green spaces in cities globally. The tool can also be used as ‘quickscan’ for urban spatial planners that would like to orientate on possible effects of current and new green space design. The plugin has been tested with different experts and locations, and it will be downloadable via the QGIS Plugin manager from the project website. The GreenUr tool allows the users to estimate the impacts of green spaces on health in a given population. The main questions addressed by the current version of the GreenUr prototype are the following: - How much green space is available for the population of a specific city? - Which are the pathways through which green spaces relate to health? - Where within a city are health-related benefits of green spaces the largest? - Which are hypothetically different land-use scenarios for green spaces? - What would be the magnitude of the change in health impacts if future green space would be changed in cities? All calculations performed by GreenUr are based on methodologies established by social, environmental, and epidemiological studies identified by WHO. The computational backend used is GRASS GIS and other processing methods available in QGIS. The plugin is running any common operating system and offers a demo database.