The 1937 Liechtenstein spy affair (German: Spitzelaffäre) was a scandal involving Carl Freiherr von Vogelsang, a founding member of the Patriotic Union and editor of the Liechtensteiner Vaterland, where it was revealed that he had sent numerous letters detailing Jews in Liechtenstein to Nazi Germany. The scandal caused prime minister Josef Hoop to order the offices of the Vaterland to be searched and for any papers to be confiscated. As a result, Vogelsang promptly left the country.
The scandal was controversial within Liechtenstein politics, and the Patriotic Union called for Hoop's resignation over the issue, claiming that his actions were against the constitution. Eventually the opinions of two legal scholars determined that Hoop had not acted against the constitution, and he was subsequently acquitted of all allegations.