Many children with fragile X syndrome (FXS) have complex communication needs and may benefit from augmentative and alternative communication (AAC). This qualitative study explored how four mother--child dyads used AAC in the home. Data were collected using participant observations, open-ended interviews, and record reviews, and analyzed using grounded theory methods. Findings revealed that mothers found AAC to be a useful tool for addressing their children's complex communication needs, but practical and personal factors impacted its use in the home. This study sheds light on how mothers of children with FXS view and utilize AAC as a way to promote communication at home. Understanding parental perspectives can help to guide professionals in planning appropriate AAC interventions specific to FXS.