Previous analyses have provided extensive and in-depth insights into the external relations of Provincial Reconstruction Teams (PRTs) in Afghanistan, particularly the division of labour between them and the humanitarian assistance community. This article broadens and deepens this literature by focusing on the internal relations of PRTs, particularly the cooperation between military and civilian sections within them. It shows that the successes and failures of PRTs are not just on the part of individual advisers, officers or uncooperative partners, but can also be located in the organizational culture of a PRT as a whole. On the one hand, a PRT constitutes a forum in which diverging civilian expert, military and national interests may collide, producing a potential for a ‘clash of mindsets’. On the other, such a collision can lead to fruitful results and innovative policies in which different viewpoints complement each other.