The complex nature of multiplicative thinking can be challenging for students and teachers to navigate. We report on the impact on student learning of school-based professional learning that targeted teachers' pedagogical content knowledge related to Multiplicative Thinking. Analysis of Year 4 students' longitudinal data indicated greater growth over time in schools involved in the learning than in non-participating schools. Six schools that received additional classroom support from teaching educators, showed the greatest growth over time. These findings suggest that school-based professional learning which includes a coaching component impacts on knowledge and practice, and subsequent student learning.