This study sought to explore the science efficacy beliefs of in-service teachers from the Kingdom of Saudi Arabia (KSA) (n = 226), Pakistan (n = 130), and the United Arab Emirates (UAE) (n = 99) by administering the Science Teaching Efficacy Belief Instrument (STEBI-B) in a cross-sectional survey research design. A comparison of the three datasets indicated differences in terms of teachers’ personal science teaching efficacy (PSTE) and science teaching outcome expectancy efficacy (STOE). Teachers’ academic qualifications and experience showed relevance with the PSTE and STOE of the KSA sample but did not show relevance for UAE and Pakistan. These results have implications for teacher education programs in all three countries, which need to strengthen their teaching content and make science teachers more efficacious in order to bring about positive changes in students’ science learning. Other recommendations include: providing culturally tailored teacher education that respects the role of cultural adaptation, nationality, gender, academic qualifications, and years of teaching experience; and introducing effective professional development models to strengthen science teachers’ efficacy beliefs.