Equality is one of the most debated topics of our time. In Sweden, the work on gender equality has been shaped by the strategy of gender mainstreaming since 1994. Gender mainstreaming not only affects the undertaking of gender equality issues at the national level, but also at the local level. Despite this, there is limited knowledge regarding the implementation of gender mainstreaming in municipalities, particularly from perspectives other than feminist ones. Therefore, this study focuses on the implementation of gender mainstreaming in three Swedish municipalities and also highlights the potential impact of organizational culture on gender equality efforts. The thesis is a multiple case study that aims to study the extent to which municipal organizational culture influences the implementation process. This aim is formulated based on previous research in this field, which suggests that organizational culture affects implementation processes. The organizational culture in the municipalities is extensively examined through the lens of capability to change. The research questions are answered through text analysis of gender equality policies and interviews with officials in each municipality. The findings of this thesis show that organizational cultures in municipalities have the potential to influence the implementation of gender mainstreaming in different stages of the implementation process. The study identifies differences in the organizational capability to change, both within and between the municipalities. The study also finds that certain aspects of the municipalities’ organizational culture can affect the implementation of gender mainstreaming. Additionally, the study has found that both management models and path dependency may be factors that impact gender mainstreaming efforts, even though this was not the primary focus of the study.