Ukraine’s defence industry has become a central feature of the country’s military strategy against Russia, and the European Union (EU) understood early on the potential of cooperation with Ukraine in this sector. This CSDS Policy Brief explains how there are several challenges to integrating Ukraine’s defence industry into the European Defence Technological and Industrial Base (EDTIB). Ukraine’s integration into the EDTIB will take time, and there is not yet an EU consensus on what this integration will look like in practice. Political challenges will hamper EU-Ukraine defence industrial cooperation as individual EU member states and Ukraine discuss sensitive issues such as technology sharing and control.