A considerable body of literature has shown the benefits of lesson study, but little attention has been paid to the determinants of lesson study involvement. This study examines how teachers' participation in lesson study is affected by their attitudes towards lesson study as well as their perceived competence. A multilevel logistic regression model and a multilevel multinomial logit model are separately used to analyse representative data on active junior high school teachers in Taiwan. The results reveal that teachers' positive attitudes towards self-development are significantly correlated with complete participation as well as with partial participation in the lesson study cycle, while teachers' perceived competence only relates to complete participation. This study not only contributes to developing predictors of lesson study involvement but also provides valuable references for policymakers.