Even though large parts of a municipal administration’s work are aligned with social sustainability, this dimension has been somewhat more challenging and there seems to be a vast diversity in how it is approached. Academic literature on the systematic organization of this work is sparse. The aim of this study was to understand how Swedish municipalities organize their work with social sustainability and to find best practices. A survey among 21 municipalities and follow-up interviews with three of them were conducted. The study revealed that the organization of social sustainability work varies considerably among municipalities and that no simple patterns relating to size or existing organizational structures can be detected. Each municipality seems to be finding its own way and is more or less successful in strategically working with this area. Best practice focused on creating additional structures for collaboration across departments, with external actors, and across sectors to at least partly overcome the silo approach engrained in a municipal structure. It was also connected to the active involvement of leaders, clear mandates, and that a common vision for social sustainability was communicated. These lessons can be transferred to other municipalities and help them move towards social sustainability in a strategic way.