The purpose of this study was to compare students' and teachers' perceptions of differentiated practices, student engagement, and the qualities of an effective teacher by fostering student voice. Participants included 802 students and 867 teachers from Northern Sydney government schools in Australia. The researcher used a convergent parallel mixed methods design, including online questionnaires and face-to-face interviews. Years 5 to 12 gifted students (n = 38) from four schools acted as co-researchers at the methodological level. The student co-researchers co-designed and disseminated the student survey, and interviewed their own teachers. Significant differences were found between the students' and the teachers' perceptions of differentiated practices, student engagement, and the qualities of an effective teacher. The study's findings highlight the need for a shared understanding of perspectives by both teachers and students to foster schoolwide optimal learning and teaching processes.