This literature review focuses on the principles and practices within professional learning (PL). The literature is “partial in its coverage, is fragmented and is under-theorised” (Kennedy, 2014, p. 689). Current gaps in this review of reviews include reviews based on longitudinal studies showing impact and sustainability of PL over time; reviews of teacher identity and PL; reviews considering the ‘complex theory of teacher learning-practice’ to inform PL design, implementation, and evaluation, which Strom & Viesca (2021) argue ‘is nothing short of an ethical imperative’ (p. 209). Nevertheless, this review offers some key learnings and insights for consideration. Please note the term ‘teacher’ applies to those working in the range of educational settings: early childhood education and care (ECEC), primary and post primary.