The Transporters intervention contains 15 animated episodes that autistic children watch daily for a month and learn emotion recognition through stories depicting social interactions between vehicle characters with grafted human faces, expressing emotions. Its automated, home-based format is cost-effective. This study included four groups of young Chinese children in Hong Kong: two intervention groups (an autism intervention group and an autism + attention-deficit/hyperactivity disorder (ADHD) intervention group), an autism control group and a non-autistic group. The autism + ADHD intervention group was one that had not been separately examined before. In this study, The Transporters episodes were delivered via an App instead of the dated DVD technology. Following The Transporters intervention, both autism and autism + ADHD intervention groups improved significantly and similarly on emotion recognition and were more like the non-autistic group, while the autism control group did not. Learning was generalizable to novel situations/characters. There was no dosage effect, with the standard recommended number of episodes viewed as sufficient for significant improvement. Besides confirming the effectiveness of The Transporters for young Chinese autistic children, this study contributes to the literature/practice by expanding the range of applicability of The Transporters to autistic children with ADHD, which is important given the high co-occurrence rate between autism and ADHD. Trial Registration: This study was registered with the German Clinical Trials Register – Deutschen Register Klinischer Studien (DRKS) on 23 December 2018. The Trial Registration Number (TRN) is DRKS00016506. Lay Abstract The Transporters App is an intervention programme with 15 animated episodes that teach emotion recognition skills to autistic children between 4 and 6 years of age. Each episode contains a story depicting social interactions between characters in the form of a vehicle, with human faces grafted on to each of them. Each episode teaches a specific emotion in a story context. Autistic children watched at least three episodes at home for about 15 min daily for a month, with parental guidance. Its automated, home-based format is cost-saving and readily accessible. This study translated The Transporters to a Cantonese-Chinese version. Results showed a significant improvement in emotion recognition following viewing The Transporters in a group of Hong Kong Chinese autistic children, between 4 and 6 years of age, with and without attention-deficit/hyperactivity disorder ( n = 48) relative to a control group ( n = 24). A non-autistic group ( n = 23) showed that the autistic children scored lower in emotion recognition pre-intervention. Post-intervention, the autistic children had improved in emotion recognition to the level of the non-autistic children. The autistic children in the intervention groups also generalized their learning to novel situations/characters not taught within The Transporters. There was no dosage effect, with the standard recommended number of episodes viewed being sufficient to achieve significant improvement. This study confirms the effectiveness of The Transporters for Chinese autistic children and contributes to the literature/practice by expanding the range of applicability of The Transporters to autistic children with attention-deficit/hyperactivity disorder, which is important given the high rate of co-occurrence between autism and attention-deficit/hyperactivity disorder.