Abstract--Shorter product life cycles require shorter innovation cycles which forces companies to launch new innovative products on the market at increasingly shorter intervals to stay competitive. A promising approach to face this challenge is described as the new paradigm of Open Innovation (OI) where knowledge of external partners (e.g. suppliers, product users or universities) is used to accelerate the company internal innovation process. Thereby, the motivation of external partners is, among other things, crucial for the success of an OIcollaboration. So far there is no systematic approach available in literature that provides guidance for finding the right "levers" to motivate these external partners to contribute their knowledge within an OI-collaboration. For this purpose, the present paper provides a methodology for identifying appropriate measures to motivate external partners depending on the type of cooperation (e.g. Idea Platform, Lead-UserWorkshop or Cross-Industry Innovations). Based on existing models in the research field of motivation psychology, suitable motivational factors are derived and considered. Finally, an interactive software-tool for raising the usability of the methodology is introduced.