The neuropsychological profile associated with sex chromosome trisomies (SCT) is frequently characterised by delays or deficits in linguistic development. Although maternal input could have an important role in influencing and shaping the linguistic development of children with SCT, there is a lack of studies in the literature that have investigated its prosodic characteristics. The study aims to analyse the prosodic features of the maternal input addressed to a group of 8-month-old children with SCT and a group of typically developing (TD) peers. Nineteen mother-child dyads with children with SCT and 19 mother-child dyads with TD children participated in the study. Maternal utterances were collected during video-recorded play sessions, and for each dyad, 50 maternal utterances were selected and analysed using the software Praat. The results showed that the maternal input produced by the mothers in the SCT group was characterised by a significantly lower pitch, less marked and modulated melodic contours, and a shorter final syllable duration than the input addressed to TD children. The prosodic features found in the maternal input addressed to children with SCT were not those expected in the maternal input addressed to children at this developmental stage and could create a non-optimal linguistic environment.