Recent research has examined patients’ drawings of their illness as a means to identify patients’ illness representations. The aim of this systematic review was to examine which representations are evident in patients’ drawings, and whether drawing assessments are associated with patient outcomes. Ten electronic databases were searched for published journal papers in English up to 1 July 2017. Narrative synthesis summarised findings by participant characteristics, study design, illness representations, and associations with outcomes. There were 101 eligible studies, published across 29 different countries, with 27 different disease categories; 54 of the studies were with adults and 80 were cross-sectional. All core illness perception domains were evident; the most common being identity and related concepts (including symptoms, anatomy, pathophysiology), and emotional representations (including fear, denial, stigma). Perceptions of treatment and the clinical and social environment were evident. More organ damage drawn and larger drawing size were associated with worse perceptions and health outcomes, and drawings distinguished between patient groups. Limitations include the inability to conduct meta-analysis. In conclusion, patients’ drawings reveal additional domains of illness representations, specifically perceptions of pathophysiology, treatment and social environments, as well as illness pre-occupation. These findings expand theories of self-regulation and suggest image-based intervention strategies.