Language teachers' self-efficacy beliefs have previously been defined as these teachers' beliefs in their abilities to support language learning in various task-, domain- and context-specific cognitive, metacognitive, affective and social ways (Wyatt, 2018a, 2018b). Nevertheless, although this definition suggests a link between learning and teaching, the burgeoning fields of inquiry into language learners' self-efficacy (LLSE) and teachers' self-efficacy (LTSE) beliefs (each numbering over one hundred studies in the 21st century) have developed separately. Notwithstanding research in mainstream education that suggests a link between efficacious teachers and motivated learners (Zee & Koomen, 2016), burning questions that remain largely unanswered include the following: What are the relationships (causal/reciprocal/and how strong?) between LLSE and LTSE beliefs in key dimensions of language learning? And how are these relationships mediated by L2 proficiency? This article aims to make connections between the fields of LLSE and LTSE beliefs explicit, with a view to supporting independent reflexive professionalism (Leung, 2009) amongst researchers. It recommends that researchers of LLSE beliefs (who tend to have a teaching role in the contexts they are researching) and researchers of LTSE beliefs (who tend to be teacher educators or academics conducting investigations across multiple institutions they do not teach in) strive to combine their research endeavors.