This preregistered study examined how a collaborative school culture and schools' collective efficacy are related to educational professionals' attitudes, personal self-efficacy, and classroom practices concerning education for high-ability students based on survey data from 875 educational professionals (teachers, counselors, and school leaders). Multilevel analyses indicated that a collaborative school culture was positively related to educators' personal self-efficacy, but negatively to their attitudes toward special provisions for high-ability students. Collective efficacy for teaching high-ability students positively related to educators' personal self-efficacy and attitudes toward special provisions for high-ability students, as well as teachers' differentiated classroom practices for high-ability students. Overall, a collaborative school culture and collective efficacy for teaching high-ability students were mostly associated with positive outcomes in educational professionals (teachers, managers, and school counselors).