ESL environments are often spaces where the negotiation of responsibility for students may affect a teacher's sense of responsibility in unique ways. Without a sense of responsibility to apply one's competence, the impact on student learning will be minimal. The purpose of the present study was to identify factors that shape elementary ESL teachers' sense of responsibility. Ten ESL teachers across four districts in two states participated in this phenomenological study. Findings indicate that sense of responsibility pertained to obtaining the necessary knowledge and skills to be effective with ELLs, student academic progress, and non-learning outcomes such as student well-being outside the classroom. This sense of responsibility is affected by the supports and obstacles in the environment and impacts the emotions teachers experience. These factors all shape the boundaries teachers create regarding their sense of responsibility. Implications are discussed.