The United Nations (UN) was established in 1945 with the aim of promoting global peace and security, and has since undertaken numerous peacekeeping operations in conflict zones. In the post-Cold War era, the shift from inter-state conflicts to intra-state conflicts necessitated a shift from traditional peacekeeping to robust peacekeeping. In some instances, robust peacekeeping has involved the inclusion of third-party counterterrorism operations. In Mali, the UN's Multidimensional Integrated Stabilization Mission (MINUSMA) and the French counterterrorism operation Barkhane have been operating side by side since 2013. The inclusion of counterterrorism operations within UN peacekeeping has raised concerns regarding impartiality. Therefore, this thesis seeks to examine the relationship between impartiality and the involvement of a counterterrorism operation in the case of Mali. A qualitative content analysis will be used to analyse reports and meeting records from the UN, using a theoretical framework of impartiality based on Emily Paddon Rhoads' research. This thesis argues that the collaboration between MINUSMA and Barkhane had implications for the impartiality of the peacekeeping operation. However, further research is needed to determine whether this applies to other peacekeeping operations which involve counterterrorism or third-party force operations. This thesis highlights the need to redefine or re-evaluate impartiality in UN peacekeeping, given the move towards robust peacekeeping and the inclusion of counterterrorism. By examining the case of Mali, this thesis contributes to the field of war studies by shedding light on the challenges and implications of including counterterrorism operations in UN peacekeeping.