The National Staff Development Council determined that high quality teaching requires setting forth ambitious goals for students and educators and making significant changes to the existing curriculum, instruction, assessment, and leadership practices. The Council suggested that this could be achieved through intense, well-designed professional learning that provides support to teachers and focuses on learning goals for students, teachers, and administrators. Furthermore, the No Child Left Behind Act directed school districts to provide teachers with an ongoing and targeted high quality professional development that focuses on teaching and learning. Information technology plays a critical role in making online training affordable and accessible.Given the importance of this issue, this study examined the effects of two formats of professional learning, face-to-face and online training, on teacher knowledge and confidence to co-teach. Sixty middle and high school general education and special education teachers from a semi-urban county received training on the six models of co-teaching, teacher roles and responsibilities, and teaming strategies. Quantitative data were collected using pre and posttests of knowledge and confidence and qualitative data were obtained using open ended questions and discussions. Results of the study indicated: (1) both face-to-face and online training significantly increased teacher knowledge to co-teach, (2) there was no significant difference in teacher knowledge between the two formats, (3) face-to-face training significantly increased teacher confidence, but online training did not increase confidence, and (4) there was a significant difference in teacher confidence to co-teach between the face-to-face and online training format.These results have important implications for educators, developers of curriculum, and administrators of face-to-face and online training programs. These are discussed further in the paper.