The purpose of the present study is to compare the perceptions of teachers representing opposite ends of the self-efficacy spectrum regarding the effects of the principal's behavior on their professional self-efficacy. In the first quantitative stage, a statistical procedure was conducted to identify the two groups of teachers: a group of 16 teachers with a high self-efficacy and a group of 14 teachers with a low self-efficacy. In the second and main stage, the qualitative stage, the teachers were asked about their professional successes and failures, using in-depth, open-ended interviews. Data were analyzed using grounded theory. Five categories of management style were found pertinent to both groups: modes of communication, feedback from the principal, social atmosphere, strength of the principal, and shared values. Differences found between the two participant groups regarding each management style category are discussed. Findings also indicate that the human aspect of teacher-principal relations is the decisive factor determining those teachers' sense of professional self-efficacy.