Discussion on organizational citizenship behavior (OCB) among teachers has gained much interest among scholars. However, a review of past literature indicates no specific instrument developed for measuring teachers’ OCB in Malaysia. Most studies pertaining to the OCB of teachers in the country have adopted instruments previously developed in the Western context. Therefore, this study aims to generate items that can truly measure the OCB of teachers in the Malaysian context. This study employed two types of research approaches involving the collection and analysis of both quantitative and qualitative data. Stage one involved 64 secondary school teachers, while stage two comprised 14 teachers who participated in a Focus Group Discussion (FGD). The result found 35 behaviors that have been identified as the OCB of teachers in Malaysia, where 18 behaviors were specific to the OCB of teachers in Malaysia and 17 behaviors were adapted from existing instruments developed in the Western context. A total of 24 items measuring teachers’ OCB in the Western context were dropped because they were considered tasks related to the performance of teachers in Malaysia. The findings show that OCB among teachers in this country should be measured using an instrument specifically designed to suit the local context. Furthermore, there are several differences in behavior with regards to teachers’ OCB in Malaysia compared to those in the Western context. Therefore, this study extends the existing body of knowledge about measuring OCB.