The current article examines the effects of teacher classroom autonomy and school culture on collective teacher innovativeness, through integrated professional learning. This examination draws upon an analysis of TALIS dataset 2018 gathered from 241 426 teachers of 15 672 schools in 48 OECD countries, using a multilevel structural equation modelling approach. The article underscores the importance of enhancing teachers' sense of classroom autonomy and collaborative school culture to promote collective teacher innovativeness. It suggests that a collaborative culture would encourage teachers to participate in integrated professional learning activities, and that collective participation in professional learning would enhance teachers’ collective innovativeness.