The American Psychiatric Association defines autism spectrum disorder as a neurological illness, in which children with the disorder have trouble communicating socially or have a set of behaviours that are recurrent or restricted. Autism learners are mostly visual method learners who learn best through pictures and visuals. Most learners with autism struggle to learn new terminology due to their cognitive difficulties, and with the advent of the Fourth Industrial Revolution, technology is no longer a foreign concept in the educational sphere. The usage of augmented reality technology has proven to be beneficial in offering more relevant learning sessions for autism learners. As a result, underpinned by the learning theories of behaviourism, constructivism, connectives and cognitivism, altogether with the theory of mind and Frame model, an augmented reality smartphone application, called ‘AReal-Vocab’, was created to assist children with mild autism in acquiring English vocabulary. The design and development research approach was employed in this study, in which later, the developed mobile augmented reality application was then tested on six mildly autistic youngsters to see how well the designed and developed augmented reality mobile application aided them in acquiring the English language. The AReal-Vocab mobile application, which was planned and built, has had an impact on the English-vocabulary learning of children with moderate autism, according to the findings. Not only has AReal-Vocab helped mildly autistic children learn English vocabulary in a more engaging and meaningful way, sparking their interest in the language learning process, but it also serves as a platform for instilling leisure learning at home, as well as stimulating pronunciation skills and language articulation. The findings of this study are expected to benefit all parties involved, particularly children with autism, autism educators, and parents of children with autism.