Winnicott’s (1968, 1993) play technique squiggling was piloted as a measure of creative thinking abilities and a potential diagnostic aid in the assessment of Asperger syndrome. The internal consistency and inter-rater reliability of squiggling was found to be acceptable. Mixed results were found between the six subscales in terms of concurrent validity with the Torrance Tests of Creative Thinking (TTCT: Torrance, Bal & Safter, 2008). Squiggling subscales Elaboration and Imagination showed signs of psychometric strength. However, Fluency and Originality require revision. Concurrent validity of the subscales Flexibility and Integration were not established. A matched-participants design enabled testing of hypothesised differences in creative thinking abilities with children with Asperger syndrome using the TTCT (Torrance et al., 2008): Abstractedness, Fluency, Originality, Integration, Elaboration, Resistance to Premature Foreclosure and Flexibility. Children with Asperger syndrome demonstrated a significantly higher level of elaboration and abstract imagination in their drawings relative to a comparison group of typically-developing children matched on age, visual motor integration ability and non-verbal IQ. Findings indicate partial support for the Weak Central Coherence Theory (Shah and Frith, 1983) and Leslie’s (1987) Meta-Representational Deficit hypothesis. Children with Asperger syndrome demonstrated understanding and expression of abstract concepts as graphical representations, thereby supporting their use in clinical assessments and interventions. No support was found for the Executive Dysfunction Theory (Pennington & Ozonoff, 1996) or for the Hyper-Systemising Theory (Baron-Cohen, 2006). Some limitations include the heterogeneity of the clinical group, and the possible confounding effects of verbal intellectual abilities, extrinsic rewards and performance anxiety. Major strengths of the study include a successful matching procedure and the finding of group differences with large effect sizes on particular creative thinking abilities.