Sucitawarni, SucitawarniAlfirman, Alfirman2019-04-302019-04-302019-04-30wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/9685Autism is defined as a complex developmental disorder involving communication, social interaction and imagination activity. With expert system can be created that can help diagnose autism spectrum for children. The reasoning process in this expert system use a backward chaining method that will prove the assumption of the disease suffered by tracing back to the symptoms experienced to obtain a treatment solution. This expert system design use UML (Unified Modeling Language). This research produced an expert system diagnosis autism for children use web-based OOP (Oriented Object Programming). The testing in this research are Black Box Testing and User Acceptance Testing. The results of the Black Box Testing are valid which indicates that the system functionality is running well. Whereas from User Acceptance Testing, users feel helped which this expert systemenWeb-basedAutismBackward ChainingExpert SystemArticle