Effects of a training program utilized to teach how to conduct functional analysis process to teachers of children with developmental disabilities was examined. Furthermore, teachers' opinions regarding this process were investigated. A multiple probe design across subjects with probe conditions was used. Teacher training was in two phases. In the first phase, teachers were given information about functional analysis methods. Then, in the second phase, teachers were asked to implement the functional analysis process with their students who had problem behaviors. Results showed that the training program was effective in teaching special education teachers how to conduct a functional analysis process. However, teachers needed intensive consultation about how to conduct the functional analysis process during the study. Responses of teachers to Social Validity Form revealed that opinions concerning functional analysis changed positively after training.