CIES 2018 Presentation, given by Matthew Jukes. There is an increased demand for assessments of social and emotional competencies of young children in low- and middle-income countries. These competencies are increasingly seen as important for children’s development and for their education. In the context of preschool and primary education, such assessments have a number of uses. They are used to evaluate the impact of programs on children’s social and emotional learning. They can also be used to monitoring individual children’s progress in such programs and to tailor interventions to their needs. We developed a tool to assess aspects of SEL that are important for children’s education in Tanzania. Using this work as a case study, we describe the challenges inherent in developing such a tool. The tool was developed as part of the USAID Tusome Pamoja preschool program in Mtwara, Southern Tanzania.