Non-UN peace operations are becoming an increasingly important conflict mitigating tool. Whilst many studies find these operations unable to mitigate conflict and promote peace, the explanations for these findings mainly focus on material aspects like mission size and peacekeepers’ capability. In order to better understand the discrepancies between UN and non-UN peace operations’ success, this thesis argues that UN operations might be more efficient due to higher perceived legitimacy. In order to analyze whether the superior legitimacy of the UN explains their higher ability to mitigate conflict, this study analyzes whether non- UN peace operations authorized by the UN are more able to mitigate conflict than non-authorized peace operations. The argument is tested by applying an OLS regression to a data frame including all intrastate conflicts between 1993 and 2016 to study the covariation between conflict intensity and the presence of UN authorized and non-authorized peace operations. The results do not support the hypothesis that UN authorization increases non-UN peace operations’ conflict mitigating abilities. This suggests that material factors might better explain peace operations’ success or that UN authorization does not substantially increase the perceived legitimacy of non-UN peace operations.