Globally prevalent, Autism Spectrum Disorders (ASDs) have negative consequences on students’ social, intellectual, emotional, and post-school transition results. While assessment tools exist, the majority of them were developed from the perspective of clinical psychology and/or healthcare. Some are lengthy and commercialized, and some have weak factorial validity. A feasible and practical assessment method, from the perspective of educational psychology and assessment, is required to better accurately and effectively assess the social and academic performance of ASD students in inclusive settings. With an emphasis on teachers’ practice and output in helping students with ASD in inclusive education, this study evaluated the Practice and Product Inventory of Supporting Students with ASD (PPI-SSA) psychometric qualities. PPI-SSA was designed to be practical, concise, and especially suited for quantitative research on ASD. The inventory was administered to 411 teachers in Hong Kong, and exploratory and confirmatory factor analyses confirmed the PPI-SSA’s reliability and validity. A follow-up path analysis examined the concurrent validity of the PPI-SSA, revealing significant pathways between teachers’ intentions to implement inclusive education and each of the respective dimensions within the PPI-SSA. Measurement invariance results showed that the PPI-SSA demonstrated configural, metric, scalar, and residual invariance across primary and secondary teachers. The PPI-SSA, as a non-commercial instrument, has meaningful implications. It can facilitate the efficient collection of more empirical data on the social and academic achievements of students with ASD, informing evidence-based improvement of inclusive practices. It can assist in teachers’ practice to identify the diverse social and academic needs of students with ASD to align with their corresponding adjustments of teaching strategies. Copyright © 2023 by the authors.