As the main operational tool of the EU Cohesion Policy, the European Regional Development Fund (ERDF) aims to invest in regional development initiatives at the regional administrative level in the member states. Hence, governed by European legal regulations, the ERDF tend to initiate policy change and policy adaptionconcerning regional development policies on the regional administrative level. Consequently, this thesis addresses the issue concerning through which functions the ERDF influences the Regional Development Strategy for Västra Götaland 2021–2030, which constitutes the operative strategy on regional development policy in Västra Götaland, including goals, priorities, and methods. By utilizing Europeanization as theoretical framework, constituted by three factors of Europeanization, concerning a supranational factor, a multilevel governance-factor and a policy network-factor, the ERDF functions influencing the strategy were distinguished and explained. Through a theory consuming analysis, this thesis conclude that the ERDF influences the regional development strategy for Västra Götaland through three functions; through the incorporation of European discourses into the strategy, which were established by the European legal acts governing the ERDF; through the multilevel governance system managing the ERDF, which has generated an institutionalized system of cooperation between European, national and regional levels for the management of regional development policies; and,through the need to cooperate in a policy network in order to implement the ERDF regionally, as well as accomplish the regional development strategy.