A study was performed to ascertain whether service-learning projects performed by preservice teachers help them apply educational theory to classroom practice during field experiences and as in-service teachers. This study found that: (1) preservice teachers should perform service-learning projects prior to other education courses; (2) participation in service-learning projects improved performance on a measure of learning theories and developmental theories; (3) earlier student involvement in servicelearning resulted in more practical applications of theory. Students involved in service-learning projects that emphasize criticism of theory had a stronger understanding of its relation to their teaching style. Finally, students participating in problem-based projects made closer connections between theories learned during coursework and methods employed in the field. The results of the study are reviewed as they relate to the teaching of educational psychology and developmental coursework for preservice teachers.