Calls for increased monitoring and evaluation of education policies and practices have not, so far, included widespread and consistent assessments of the inclusiveness of education settings. Measuring inclusion in education has proven to be a challenging exercise, due not only to the complexity and different uses of the concept, but also to its holistic nature. Indeed, measuring inclusion implies analysing a variety of policy areas within education systems, while also considering the different roles of the system, the school and the classroom. This paper discusses the application of the input-process-outcome model to the measurement of inclusion in education, and key indicators that can be adopted by education systems and schools to this end. It makes considerations relevant to policy makers when designing indicators to measure inclusion, such as the extent of their application, the constraints related to data disaggregation and the relevance of intersectional approaches to inclusion.