In times of reform and crisis, innovation is central for adapting to change. Many companies currently adopt open innovation models in an effort to increase their innovativeness. However, not all companies practice identical modes of open innovation and the adoption of open innovation models doesn’t lend itself to predictable cause-and-effect relationships. The adoption of open innovation models varies among companies and is dependent upon influencing determinants. Hence, each company has to analyze their specific external and internal influencing factors and adapt the open innovation models accordingly. Grounded in case studies of innovation management of public utilities, we aim to develop a conceptual framework regarding external and internal factors that influence the adoption of open innovation. The goal of our research is to contribute to the field of open innovation by answering questions pertraining to when, why, and how companies adapt open innovation models according to the various influencing factors.