This mixed methods survey study aims to investigate school staff's perspectives on using augmentative and alternative communication (AAC) with students with the most severe disabilities in Swedish school settings. The study employed a convergent mixed methods design, where both quantitative and qualitative data were collected and analysed in parallel and then integrated and compared in the discussion and conclusion section of the paper. The study's respondents consisted of school staff who worked with students with severe or profound intellectual and multiple disabilities (S/PIMD) in Swedish schools. Results showed that almost all staff reported using AAC with students at least half of the time. The frequency of AAC use did not seem to differ between staff with different educational backgrounds, apart from teachers/special educators appearing slightly more inclined to use AAC in planned classroom activities when compared to staff with other educational backgrounds. The results also corroborate previous research stating that collaboration between stakeholders (such as school, family and the habilitation services) is fundamental to successful AAC implementation but that there are challenges when establishing efficient collaborations between stakeholders.