Purpose: Interest in gamification as a relevant and innovative pedagogical tool has increased in recent years among academics and educators. While considerable literature has focused on the effectiveness of gamified learning, little is known about the motivations behind its adoption. By examining teachers' perspectives, which are often overlooked, we investigated the factors influencing teachers' adoption of gamification strategies. Design/methodology/approach: We adopted Korthagen's onion model as the main theoretical lens to identify the influencing factors. A qualitative study involving interviews with 15 French higher education teachers was conducted to achieve our purpose. Findings: The results were organized within the six layers of the onion model, through which we demonstrated the factors influencing teachers' adoption of gamification. The institutional environment and teachers' internal characteristics (beliefs, values, identity and mission) were identified as the determinants of gamification use. Originality/value: Unlike most gamification studies, this research contributes to the literature by considering teachers' perspectives and integrating the Korthagen model into the educational setting. We also propose an integrative theoretical approach that uncovers synergies between the Korthagen model and the educational leadership literature.