In this study, we theoretically and empirically investigate the determinants of Bt maize adoption in German regions. Specifically, we ask how the regulatory framework, the farm structures as well as the socio-political environment of GM expansion in Germany have influenced regional adoption rates. Following a description of the relevant legal and economic framework in Germany, we develop theoretical hypotheses concerning regional variation in Bt-maize adoption and test them econometrically with unique data at the Federal States (Länder) and County (Landkreis) level. The study provides evidence that the adoption of Bt-maize in different regions is positively affected by the amount of maize grown per farm and by the European Corn Borer (ECB) infestation rates. There is also some evidence that the Bt-maize adoption is negatively affected by the activities of the anti-GMO movement and the establishment of GMO-free zones.