The Research for Effective Education Programming – Africa (REEP–A) Task Order, awarded in September 2016, is a five-year project within the United States Agency for International Development (USAID) Africa Bureau. The primary objective of REEP–A is to generate and effectively disseminate Africa regional and country-specific education data, analysis, and research to inform the prioritization of needs and education investment decisions. One research focus under REEP–A is to explore how teachers’ language proficiency and literacy in the language of instruction (LOI) influence students’ learning outcomes. It is hypothesized that the teachers’ level of language proficiency and literacy in the LOI can either facilitate student learning, if high; or impede learning, if low. However, limited data are available on how teacher language and literacy skill levels precisely relate to student outcomes. Exploring this relationship requires having a valid and reliable tool to measure teachers’ language and literacy skills. USAID therefore commissioned the development of the Teacher Language and Literacy Assessment (TLLA) to assess teachers’ language proficiency and literacy in the required LOI. The TLLA, adaptable to any language, consists of subtasks assessing speaking, listening, reading, and writing, as well as vocabulary and grammar, in the language(s) used for teaching and learning at the primary school level in a given context. It is envisioned that policymakers, researchers, and other education stakeholders can use the TLLA to collect data on teachers’ linguistic assets and gaps in the languages that their role requires them to use. These data could be useful for identifying factors contributing to student learning outcomes, informing teacher training and professional development needs, designing teacher deployment policies, and evaluating the impact of interventions aimed at improving teachers’ or students’ language and literacy skills. The aim of this report is to present the new tool and disseminate the initial findings around its technical adequacy. The international community has directed considerable effort to assessing and understanding the impact of language on students’ literacy and language skills, and the TLLA is a complementary tool that shows promise for understanding teachers’ language assets and needs.