Sotos syndrome is a genetic disorder of mental retardation characterized by specific facial characteristics, overgrowth in childhood, cognitive impairment and speech and language difficulties. In this paper, we report on a single case study of a female adolescent, TK, aged 15;9 diagnosed with Sotos syndrome. The main goal was to investigate her phonological short-term memory abilities as well as her visuospatial memory abilities and language abilities. We employed the following tests: (a) Raven’s Progressive Matrices and Vocabulary Scales (Greek edition) (Raven et al., 2003/2004), (b) Renfrew Word Finding Vocabulary Test – Greek edition (Vogindroukas et al., 2009), (c) Peabody Picture Vocabulary Test –Special Edition (Greek edition) (Simos et al., 2012), (d) Action Picture Test – Greek edition (Vogindroukas et al., 2011), and (e) Bezevegis et al.’s (2008) memory test. The most profound deficiencies were observed in expressive vocabulary and pragmatic/communicative skills, while difficulties were also found in verbal short-term memory. Deficiencies were also observed in verbal and non-verbal IQ in agreement with previous findings (Cole & Hughes, 1994. de Boer et al., 2004. Finegan et al., 1994). TK’s performance on visuospatial sketchpad was slightly better compared to the results obtained through the other tests. We discuss the clinical implications of our findings.