Histories of southern German firms during the Second World War suggest that Switzerland provided many highly-skilled labourers for Germany’s war effort, but no study has to date quantified these contributions. This paper examines the labour exchanges between the two countries, focusing on individuals working within a free movement and trade area in the border region of Switzerland and Germany. A maximum of 1,800 Swiss workers is ascertained to have worked in the German part of this area, representing 7.5% of the total labour force, 12% of the highly-skilled labour force and over 20% of the metal workers in the ten-kilometre German zone. Swiss contributions are somewhat offset by Germans working in the Swiss zone. Most importantly for Swiss neutrality, this papersuggests that, despite initially supportive increased labour transfers at the start of the war, the Swiss government sought from 1941 to prevent workers from transferring to Germany.