This chapter explores various European moments when Europeans have engaged with civil and military use of nuclear energy. While the development of nuclear power was initially closely and deliberately linked to (re‐)building Europe and European integration, since the 1970s, the growing critique of this technology has given rise to conflicts within societies and across borders, transnational movements, and European networks of cooperation. In the beginning, this was limited to Western Europe, but since the Chernobyl disaster of 1986 it has increasingly included the East as well. This chapter draws on European moments that have played out on - and often cut across - different levels, from the supranational to the national and local, in different parts of Europe, shaped by a variety of different actors. It underscores, in particular, the important role played by women in this conflict.