Eastern Ukraine has been affected by conflict since 2014, resulting in large numbers of people requiring humanitarian assistance. Throughout the different phases of the conflict, numerous lessons have been learned by humanitarian actors. This report outlines lessons learned in three categories, protect (protecting civilians, humanitarian access and civil-military coordination), prioritise (prioritising effective humanitarian assistance to people in greatest need), and prevent (preventing and anticipating future shocks and rebuilding resilience in protracted and recurring crises). There is a limited body of literature on lessons learned from humanitarian interventions in the Ukraine. Evaluations provide some evidence on best practices and areas for improvement, but these are limited in number. While these evaluations often provide lessons learned and recommendations for specific organisations, many of these are applicable for other international humanitarian actors operating in Ukraine. While Ukraine has a well-established social protection system, there is limited evidence on the use of existing social protection mechanisms to channel assistance. The existing literature on humanitarian interventions in Ukraine between 2014 and 2021 discusses persons with disabilities and the elderly from the perspective of inclusion in programming. There are also numerous gender analysis reports of conflict-affected areas, and gender is addressed in the context of gender mainstreaming in humanitarian interventions within programme evaluations.