This case study explored the process of English as a second language (ESL) teachers' participation in online self-and peer assessment (OSA and OPA) during an online teacher professional development (TPD) program focusing on task design and their perception of the subsequent impact on their understanding of tasks.How to cite this article: Singh, S., & Mahapatra, S. ( 2022). Online self-and peerassessment for teacher professional development: A case study of the process and the perceived impact.