Research on the potential benefits of technology for autistic children is an emergent field in Human-Computer Interaction (HCI), especially within the Child-Computer Interaction Community. This thesis contributes a design approach grounded in theories of play, cognitive development, and autism to expand the discourse on methodological guidelines for performing empirical studies with non-verbal autistic children and to extend the design space to cater to the socio-emotional and sensory needs of this population. The thesis reveals how sonic e-textile Tangible User Interfaces (TUIs) can be used effectively to mediate children’s social participation in playful activities. This is demonstrated through developing three explorative field-studies conducted at a specialist school based in North-East London where two sonic e-textile playful TUIs, namely Mazi and Olly, have been created and tested with three groups of autistic children aged between 5-10. The three studies ran over the period of three years and were designed to investigate the potentials of TUIs as shareable toys during leisure and recreational activities to a) support social and playful interactions among peers and b) provide opportunities for self-regulation. The key contributions of this thesis are the designs of two tangible user interfaces, which offer a set of design approaches to guide researchers through creating shareable and playful tangibles for non-verbal autistic children; a framework for analysis and a thorough evaluation process that other researchers could use to assess the efficacy of playful TUI designs for nonverbal autistic children; and an in-depth discussion about the research process, which offers a new perspective about holistic designs and evaluation of technologies that aim to scaffold play in groups non-verbal autistic children
