This study examined English Learners' (ELs) self-efficacy beliefs in a U.S. university setting by using a survey, interviews, and focus group discussions. The results identified that ELs from different disciplines had positive self-efficacy beliefs about their overall English learning, and self efficacy was related to ELs' age, years of English learning, country of origin, and previous educational level. However, ELs in this study lacked confidence and self-efficacy in learning in academic courses, and they faced challenges when using academic language. Effective instructional strategies such as social modeling, social persuasion, motivational feedback, group work, and participative assessment methods were identified by ELs in this study.