Self-efficacy is a parameter capable of predicting change in teacher behavior. We designed a questionnaire to investigate self-efficacy for promoting Education for Sustainability (EfS), which includes pro-environmental behaviors and environmental attitudes, to answer the question: "What characteristics of self-efficacy for promoting EfS among pre-service teachers allow promotion of EfS in the private and public spheres?" Findings reveal that skill is the key predictor of self-efficacy in promoting EfS. The characteristics of a pre-service teacher with a high level of self-efficacy for promoting EfS included positive attitudes towards the environment, pro-environmental behaviors in the private and public spheres, and belief in the EfS course providing relevant skills for promoting EfS. Outside of the school, a high level of self-efficacy is characterized by pro-environmental behaviors in the private and public sphere. We conclude that EfS courses should emphasize skills as a key to increasing self-efficacy in promoting EfS.