Although hundreds of thousands of soldiers from different national contingents are deployed every year in multinational peace operations, no previous study has examined differences in peacekeeping practices along national lines. This paper first documents systematically differences in the way national contingents behave during peace operations in their respective area of operation. In a second step, it argues that these differences in behavior are largely consistent with the most important traits of each army's military culture. Based on extensive fieldwork conducted between 2007 and 2014 in Lebanon and Afghanistan, the paper shows how, within each mission, Italian soldiers prioritized humanitarian activities, while the French engaged in more patrolling activities, despite being both contingents deployed under similar conditions. These variations in behavior are consistent with the way French and Italian soldiers perceive the mission and context in which they deployed. And both the differences in behavior and perception are in line with the respective armies' military cultures. This paper contributes to the debate on the role of ideational factors in international politics and in particular to the ongoing discussion on strategic and military cultures.