An increased involvement of citizens in the management of European green spaces raises questions about its contributions to nature conservation. In this research, we study the effects of different types of active citizenship in green space. Combining qualitative and quantitative methods, we look at the benefits of 50 green self-governance practices in which citizens aim to realize, manage or protect green space in the Netherlands. While most of these practices contribute to nature conservation (80%) and/or the conservation of cultural landscapes (50%), our analysis shows that the benefits of green self-governance are much broader. This includes so called ‘co-benefits’, social, cultural and economic benefits such as the use function of green for human activity (78%), environmental education (88%) and social cohesion (50%). The benefits and co-benefits of green self-governance strongly depend on the type of practice. Using a typology of green self-governance, we show that a majority of practices focuses on direct benefits to nature conservation through hands-on activities and/or political actions. However, we also show that this focus is regularly combined with efforts to realize co-benefits. Practices with an explicit focus on co-benefits often also produce benefits - and vice-versa. In this way, co-benefits can provide a first step towards the realization of more direct benefits to nature conservation. Even so, there are also tensions between benefits and co-benefits, for example when an increase of recreation negatively affects biodiversity values or when ‘wild’ nature is being replaced by a cultivated garden. Relating to co-benefits can be an effective strategy for governments or environmental NGO's, but we have to be aware that the benefits generated by green self-governance are generally of a much smaller scale than those realized by ‘traditional’ managers of green space such as authorities.