This preliminary study was designed to help two teachers who felt excessively self-critical to increase their positive self-thoughts and decrease their negative self-thoughts, i.e., to improve their self-esteem. An intensive experimental design involving four phases was employed. Each phase--Baseline, Thought Stopping, Positive Intervention, and Follow-Up--lasted approximately 2 weeks. During all phases of the experiment the teachers observed their positive and negative self-thoughts with the help of wrist counters. Classroom observers coded instances of overt positive and negative behavior by the teachers. A positive intervention, which used stimulus cues to prompt positive self-thoughts, was effective in increasing the positive thoughts of one teacher. The results of thought stopping (subvocalizing the word "stop" to inhibit unwanted thoughts) were mixed. The reported changes in self-thoughts were supported by two self-report measures and, to some extent, by the external observations of teacher and student classroom behavior. Some indication was found that self-observing does change the behavior being observed. (Authors)