This report outlines the development of the CLIL Provision Questionnaire: an instrument used by CLILNetLE’s (CA21114) Working Group 1 to investigate how programs teaching nonlanguage content through foreign and additional languages are conceptualized, organized, and implemented across Europe. The present report is intended to accompany the instrument itself (CLILNetLE Working Group 1, 2026), which is also available on the CLILNetLE website and the CLILNetLE collection in the PHAIDRA repository. The results of the questionnaire’s administration have been published in Gülle and Nikula’s (2024) Overview of CLIL provision in Europe and country-specific insights.