The Collaborative Teacher Inquiry Project was a professional development initiative that sought to improve the teaching and learning of Grade 9 Applied mathematics by encouraging teachers to work collaboratively. The project brought together Grade 9 Applied mathematics teachers from 11 schools across four neighboring public school boards in the same geographic area of a large urban city in Southern Ontario, Canada. Teachers formed learning communities as a result of the Collaborative Teacher Inquiry Project through active collaboration to further teachers' knowledge about teaching the Grade 9 Applied mathematics course and in developing teaching materials. Although it was reported that there were barriers to collaboration, teachers described various strategies that were (or could be) implemented to overcome these barriers. Teachers were enthusiastic in continuing to creatively find solutions to combat barriers as they saw the overall benefits of collaboration to their professional growth and noticed an increase in student engagement and achievement.