This paper analyzes the effect of exposure to foreign mass media on environmental awareness and pro-environmental behavior. We exploit a natural experiment occurring in the German Democratic Republic, where the reception of West German television was determined by geographic characteristics. Western media was a reliable source of information about environmental pollution in the German Democratic Republic, a topic that was not covered in the East German state media. Using survey data conducted before the German reunification, we find that access to Western media increased environmental awareness among GDR citizens. The analysis of data from the German Socio-Economic Panel supports this finding and reveals a positive and persistent effect on the probability of being active in environmental organizations. Finally, by examining election data, we show that counties with former West German television reception were more likely to vote for the Greens in the first two federal elections in reunified Germany.