The concept of professional learning communities (PLCs) has received considerable attention in research as well as in school practice since the late 1990s. PLCs have been positively associated with a variety of outcomes for both teachers and students, but differences in the way the concept is operationalised, and the fact that most of the research is related to specific national contexts, make it difficult to accumulate and compare research related to PLCs. In order to give PLC research an international scope, the aim of this paper is to develop a global measure of PLCs. The paper includes an overview of the literature on PLCs, as well as an examination of existing measures. Informed by these findings, multi-level confirmatory factor analysis is applied to develop a measure of PLCs in the Teaching and Learning International Survey 2018. This measure includes three distinct dimensions and an overall measure of PLCs at school level in 42 countries/economies, and is available for researchers interested in the concept of PLCs and international perspectives. The measure is applied in an example which investigates the relationship between PLCs and teacher job satisfaction in the Nordic countries. Strengths, limitations, international comparability and possibilities for future developments are discussed.