Background: There is a large gap between the needs of individuals diagnosed with autism spectrum disorder (ASD) and the currently available services in Saudi Arabia. Services are often difficult to access, inconsistent in quality, incomplete, unsatisfactory, and costly. As such, there is a national need for expert consensus on the appropriate standards for the assessment and management of children on the autism spectrum. Methodology: A guideline development group (GDC) was formed by professionals representing all related specialties and institutions involved in the management of individuals on the autism spectrum in Saudi Arabia. They met on a regular basis over 21 months. The guideline development process consisted of five steps starting from reviewing existing guidelines and ending with discussing and writing this manuscript. A formal voting process was utilized and recommendations were discussed until a consensus was reached. Results: There was consensus on the following: A specialized diagnostic assessment needs to be carried out by an experienced multidisciplinary team for children referred to assess for ASD. They should be assessed for medical etiology, their behavioral history carefully reviewed, and symptoms directly observed. Longitudinal assessments are encouraged to reflect the effects of symptoms on the individual’s ability to function while with their family, among peers, and in school settings. An additional formal assessment of language, cognitive, and adaptive abilities as well as sensory status is essential to complete the diagnostic process. Interventions should be individualized, developmentally appropriate, and intensive, with performance data relevant to intervention goals to evaluate and adjust interventions. Target symptoms must be identified to address and develop monitoring systems to track change. Conclusion: ASD is a complex condition with widely varying clinical manifestations, thus requiring evaluation and intervention by a range of professionals working in coordination. Behavioral and environmental interventions are the key to optimal outcomes, in conjunction with medications when indicated for specific symptoms. Parental involvement in interventions is vital to sustaining therapeutic gains.