This study examines the personal, institutional and macroeconomic determinants of individual votes on 36 environmental protection proposals put to vote over twenty-one years in Switzerland. It applies a hierarchical model allowing for heterogeneous voter motivations, such as economic considerations or following heuristic shortcuts. We confirm that the individual-level variables education, political afinity, car ownership and urbanity are important determinants of environmental votes. However, adding institutional and macroeconomic context variables on a second level significantly increases the proportion of variance explained. Cross-level interaction effects between motivation groups and institutional and macroeconomic variables confirm the validity of our motivation groups, i.e. favourable macro-economic conditions increase the approval rate of voters who emphasize the short-term economic impacts of the proposals. Finally, our analysis challenges the view of surveys that citizen support for environmental protection is declining in Switzerland.