There were two goals with this thesis. The first goal was to find out what the United Nations’ policy of gender was in United Nations’ peacebuilding missions as shown in United Nations Security Council Resolution 1325 on women, peace, and security and the second was to find out what the policy of gender was in the United Nations Security Council Resolution 1509, which implemented the peacebuilding mission in Liberia in 2003. I wanted to explore this topic to see how the United Nations incorporates gender mainstreaming in their peacebuilding missions and if it is possible to see if there is an understanding of gender which influences this. For my theoretical framework, I used Johan Galtung’s concepts of violence and positive peace and Harriet Holter’s perspectives on how to bring gender equality into his analysis. I have then used the concepts of Connell, West and Zimmerman to provide a theoretical framework for my thesis. To analyze the two resolutions, I have used Carol Bacchi’s “What is the problem represented to be?”-approach to critically interrogate the two documents. My main finding is that the United Nations’ gender policy consists of four themes. The themes are the use of the term “gender” to signal that the measures are directed at all genders, measures to protect women and girls from violence, references to women’s “special needs” and lastly measures to ensure that women participate in processes such as conflict resolution, promotion of peace and in political institutions. I then found that this policy of gender is also present in Resolution 1509, though in a diluted version. The thesis ended with some suggestions for how the policy of gender may be improved and some suggestions for further research.