The current emphasis of many mathematics education reform documents is on the need to change the environment of mathematics classrooms from the transmission of knowledge by the teacher to the transaction of knowledge between the teacher and the students which promotes mathematical investigation and exploration. In this article, we discuss the details of a Collaborative Teacher Inquiry Project which was aimed at increasing the quality of learning of Grade 9 Applied Mathematics, while at the same time, improving professional development opportunities for the teachers. A total of 11 schools participated in this project which spanned over three semesters. Participants included teachers, department heads, curriculum leaders, and administrators. Each school created an implementation team of administrators and teachers to implement collaborative strategies and improve teaching and learning in Grade 9 Applied Mathematics. The main benefit to the participants was that they were able to increase their knowledge and skills through collaboration in six interconnected areas: (a) achieving the goals, (b) student success, (c) professional development, (d) co-planning and co-teaching opportunities, (e) increased communication, and (f) improved technological skills. Bringing in different partners to achieve a common goal was the most challenging aspect of the project.