A politicization of diplomacy weakens the professionalism of the foreign service and arguably endangers the external relations of states. Yet, this phenomenon has largely escaped scholarly scrutiny. Public administration research on politicization usually overlooks the foreign service, whereas diplomacy scholars have focused almost exclusively on the United States. Our exploratory study of ambassador appointments compares the levels and modes of politicization (through politically connected professionals, or political appointees) of 669 ambassadors in 2019, across seven countries and three administrative traditions. The analysis is guided by three expectations: 1) countries that are more politicized overall appoint more non-career ambassadors; 2) patronage recruitment of political appointees focuses on low-hardship postings; and 3) politically connected professionals are used to control politically important foreign missions. We find that states politicize their foreign services to a varied degree and in different ways. Appointing politically connected professionals instead of political appointees is the most common way of politicization among our cases. In this regard, the US is an outlier, which also points to the need of studying politicization of diplomacy comparatively. This article thus makes an important contribution by setting the agenda for future research on this hitherto underexplored topic.