Building the Self-Efficacy Beliefs of English Language Learners and Teachers explores, juxtaposes and bridges two fields of research that have developed separately: the self-efficacy beliefs of English language learners and the self-efficacy beliefs of English language teachers. The aim is to expand understanding in each field and highlight how the two areas can mutually inform each other. This should encourage fresh perspectives, providing direction for researchers, and improving learning, teaching, and teacher education. Empirical research suggests that English language learners and teachers who believe they can fulfil a task are more likely to succeed than those who believe they cannot. Based on a deep understanding of how self-efficacy beliefs are formed and developed, this book illustrates how such beliefs can be supported and researched amongst English language learners and teachers. Bringing together the work of educators and researchers working in contexts including Algeria, Bulgaria, Canada, China, Iran, Israel, Japan, Türkiye, the UK, the USA, and Vietnam, this volume includes meta-analyses largely focusing on quantitative data and empirical studies employing qualitative approaches and mixed methods. Studies included examine factors impacting the development of language teachers’ self-efficacy beliefs and investigate domain-specific dimensions of the self-efficacy beliefs of English language learners and teachers. This rigorous and original volume will appeal to an international readership of scholars, teachers, teacher educators, and researchers with interests in language education, teacher education, TESOL, linguistics, and educational psychology.