In spite of its sensitivity, diplomatic protection has received very sporadic scholarly attention. This article provides a comparative analysis of US and UK diplomatic security policies, focusing on the increasing use of private military and security companies (PMSCs) for the protection of foreign service and development agencies’ personnel. The existing theoretical explanations of the privatization of security tasks cannot explain why countries displaying similar material incentives and similar political and market cultures have outsourced diplomatic protection to different degrees, nor can they account for variance in the use of PMSCs by different agencies within the same country. Our analysis highlights the importance of investigating organizations’ interests in providing a more accurate explanation of the varying propensity to outsource armed protection. In both the United States and the United Kingdom, the outsourcing of diplomatic security was a resultant of foreign policy bureaucracies and military organizations’ preferences.