Spelling mastery is an important prerequisite of proficiency in the English language. The conventional language teaching strategy needs to be revolutionized for the 21st century by utilizing Information and Communication Technology (ICT) to enable English as a Second Language (ESL) students to master spelling. As such, online teaching and learning becomes a crucial strategy to impart and receive knowledge. This case study focused on teaching spelling mastery via Google Classroom to elementary school ESL students, coincidently during the unprecedented COVID-19 pandemic which has resulted in the emergence of a new norm in education. This case study involved thirty mixed-proficiency Year 4 ESL students from a suburban national primary school in Selangor. These students were divided into two groups, the experimental and control groups. The experimental group comprised a class of fifteen students who participated in the intervention, whereas the control group consisted of another fifteen students who did not participate in the intervention. The research instruments included pre- and post-test results, field notes and semi-structured interviews. To maintain the integrity of the data, the researchers took the necessary measures to ensure that the instruments were reliable and valid. This included assessing the content and face validity of the research instruments, expert validation for the interview questions and adequate engagement in data collection. The principal findings regarding the use of Google Classroom revealed students' improvement and increased motivation in mastering spelling.