What personality traits represent dispositions most relevant to teaching professionals? Could an instrument reflecting work personality traits for a wide variety of professions provide a valid assessment of dispositions for teacher candidates? This study analyzed the internal structure of a state mandated dispositions assessment that was adapted from the Workplace Personality Inventory II. The analyses found that the hypothesized factor structure lacked support from the data. The second stage of the study explored and identified a measurement model consisting of select personality traits most relevant to teaching professionals. The results of the study have implications for educational agencies and teacher education programs interested in the assessment and promotion of dispositions of teacher candidates.