The significance of teacher collaboration in driving school changes has been widely acknowledged. However, previous studies have rarely delved into the relative contributions of different forms of teacher collaboration. In this study, we aimed to address this gap by identifying two forms of collaboration and examining their effects on school innovativeness and innovative teaching practice using structural equation modeling. Our sample comprised 3,835 teachers of lower secondary schools in Taiwan, drawn from the TALIS 2018 dataset. The findings of our study suggested the differential effects of the two forms of collaboration. "Professional collaboration," characterized by deeper-level engagement, was found to have a more substantial association with both school innovativeness and innovative teaching compared to "exchange and coordination for teaching." Furthermore, our analysis revealed mediation effects in the pathways examined. Specifically, school innovativeness partially mediated the effect of "professional collaboration" and fully mediated the effect of "exchange and coordination for teaching" on innovative teaching.