Teacher collaboration has been widely implemented in the secondary school setting as an integral component within a professional learning community in an effort to increase student achievement and to foster a better working environment for teachers. The effects of teacher collaboration on both students and teachers of Earth science in a high school environment were investigated in this project. Particularly, the project examined the effects of collaboration of Earth science teachers on student understanding, student motivation, and teacher motivation. Results indicated that student understanding and teacher motivation increased, while the results on student motivation were mixed. The data showed a large gain in student understanding as a result of collaboration on instruction, whereas the level of student motivation was deemed negligible. Teachers in the collaborative group were observed to have increased levels of motivation as a result of the group's collaborative efforts. The project was an enhancement of my own level of motivation as well.