Among many other characteristics, Kurdish nationalism and the Kurdish question carry strong crossborder features. Crossborder interaction between the Kurds of different parts of Kurdistan has a long history, in which crossborder solidarity has worked as an invaluable source of movement mobilisation. In this chapter, light is shed on the KDPI leadership’s attempt to re-establish the Iranian Kurdish movement in the 1960s through reliance on crossborder interactions with the Iraqi Kurdish movement, under the leadership of the KDI and Mostafa Barzani. Through this chapter the Iranian Kurdish movement’s interaction with the Kurdish movement in Iraq, and the impact of this interaction on the content and direction of the Iranian Kurdish movement, are highlighted. In addition, in order to reflect on critical aspects of this interaction, minor and major events and episodes that contribute to understanding this crossborder Kurdish interaction are included in this chapter.