The conflict in eastern Ukraine continues with little sign of a negotiated resolution. Crimea has been absorbed into the Russian Federation, and celebrates the third anniversary of its 'integration' in March 2017. The ongoing nature of the conflict contrasts with a lack of academic exploration of the issues surrounding it. To date, most analyses have focused on the geopolitical implications of the Ukrainian crisis, such as the impact on NATO-Russia relations, and foreign policy responses to the crisis from a variety of state and supranational actors including the EU and Russia. The role of sub-state and non-state actors, and implications for them, has been largely overlooked. This volume seeks to rectify this by examining a wide array of non-state and sub-state actors that have both played a role in the conflict in Ukraine and been indirectly impacted by it. It explores topics such as the popularity of the separatist movement in Donbass, the perception of local political elites, the involvement of private armies and the implications for sub-state actors across the post-Soviet space. This book was originally published as a special issue of Southeast European and Black Sea Studies.