The Maslach Burnout Inventory (MBI) was designed to assess the frequency and intensity of perceived burnout among persons in the helping professions in general. This study examined the reliability and validity of the MBI when used with one particular category of helping professionals, teachers. The construct validity of the MBI was examined by using principal factor analysis with iterations and a varimax rotation. Results of this analysis indicated that when employed with teachers, the MBI measures the same basic constructs or factors as those identified through studies in the helping professions—Emotional Exhaustion, Personal Accomplishment, and Depersonalization. However for teachers, Depersonalization separated into a job related and student related factor. Because of the high subscale intercorrelations for the frequency and intensity dimensions of the MBI, the need to utilize the two dimensional format with teachers is questioned. Internal consistency estimates of the reliabilities of each subscale of the MBI for teachers was determined using Cronbach's coefficient alpha. The reliabilities obtained for teachers were similar to those reported for helping professionals in general. Recommendations are made for improving the reliability of the Depersonalization subscale as well as for future examination of the validity of the MBI.