This White Paper presents the main results and policy recommendations from the Horizon 2020 project “Quantifying Migration Scenarios for Better Policy” (QuantMig). It discusses the uncertainty and complexity of migration processes (Section 1), assesses selected theoretical approaches for explaining migration (Section 2), reviews migration drivers in the origin, destination and transit countries (Section 3), evaluates data and migration measurements for scenario-building on future migration (Section 4) and presents ways to inform and construct migration scenarios (Section 5), followed by the project’s main conclusions and recommendations (Section 6).