This paper aims to support a process to establish a global emission inventory for per- and polyfluoroalkyl substances (PFAS). It uses perfluoroalkyl carboxylic acids (PFCAs) as a reference to present an overall picture of global and regional emissions of PFASs and other related fluorinated substances due to the numerous interlinkages between PFCAs and many other fluorinated substances. The analysis provides a comprehensive overview of the current understanding of historical and ongoing global and regional emissions of C4–C14 PFCAs and identifies critical gaps and key uncertainties in terms of data collection and integration to accurately measure global and regional emissions of C4–C14 PFCAs. The paper does not provide direct data on substances other than PFCAs, such as perfluoroalkane sulfonic acids (PFSAs) and perfluoroalkane phosphonic acids (PFPAs); however, information on and/or estimates of the emissions of these substances is an important element of understanding the global emissions of PFCAs and are provided in the background assessment and estimation. Recommendations for improving knowledge on global and regional emissions of PFAS are presented.