This research evaluates an anti-bullying program, Dare to Care: Bully Proofing Your School. Students in Grades 4-6 (N = 197, 77 boys, 120 girls) from four Calgary elementary schools completed the Colorado School Climate Survey (Garrity, Jens, Porter, Sager, & Short-Camilli, 2000) and the Provictim Scale-Short Version (Rigby & Slee, 1991). The first research component was a pretest--3-month posttest comparison between a school that was about to implement the program and one that was not planning to do so. At pretest, students in the no-program school gave more positive reports on many variables than the school about to implement the program, making the intended across-school statistical comparison unfeasible. Within the 3-month program school, however, the frequency of bullying witnessed by the students significantly decreased, but remained stable in the no-program comparison school. Further, attitudes towards victims significantly worsened in the no-program school, but remained stable in the program school. The second research component compared three schools that had implemented the anti-bullying program for various lengths of time. Students in the schools with the longer program duration reported more positive attitudes towards victims than students in the school with shorter program duration; however, other indicators of program effectiveness were not significantly different. The results raise questions about evaluating anti-bullying programs.