Municipalities play an important role in society’s transition towards sustainability. However, as they are subject to forces from both top-down (legislation etc.) and bottom-up (stakeholders’ needs and interests etc.), as well as internal dynamics within the municipal organisation, their planning approaches are usually not strategic. This implies that there is often a gap between long-term plans and short-term actions. This thesis explores enablers and barriers for strategic sustainability planning in municipalities. Focussing in particular on the översiktsplan Swedish municipalities are required to create for their spatial planning, we develop a proposal how the planning process defined by Swedish law can be made more strategic and incorporate sustainability. We suggest to integrate elements of the Framework for Strategic Sustainable Development (FSSD) into the planning process, and to engage experts and the general public from early on. Moreover, we provide a toolkit containing various instruments that facilitate using the strategic planning process proposed. Finally, this thesis shows ways to deal with forces from top-down, bottom-up and within the municipality. The suggestions build on insights from literature as well as interviews conducted in municipalities and with further experts, but have not yet been tested in a real-life context.