Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects more than 1% of children per current estimates. It has been characterised by the following two core behavioural phenotypes: (1) deficits in social interaction and communication and (2) repetitive behaviours, restricted interests and activities. Due to the complex nature of ASD, there are currently no effective treatments. The reason behind this is the clinical and genetic heterogeneity between affected individuals on the one hand and the lack of understanding of the underpinning pathophysiological mechanisms on the other hand. Induced pluripotent stem cells (iPSCs) are reprogrammed stem cells from adult cells. These have the capacity to self-renew and differentiate into any type of cells in the body. Therefore, human iPSCs provide a unique opportunity to study the human cellular and molecular phenotypes associated with ASD. Here, we systematically review various ASD variants and co-morbid diseases modelled using human iPSCs.