Objectives: To explore the knowledge of the general community in Saudi Arabia about autism spectrum disorder. Method: A cross-sectional study was conducted for the period between June and September 2021 in Saudi Arabia using an online questionnaire tool. The questionnaire tool was developed based on a literature review. The questionnaire tool consists of 34 items that assess knowledge about autism spectrum disorder in terms of its etiology, autistic patient features, autistic children’s abilities and needs, and autistic adults’ abilities and needs. The total score for each subscale was used to define the level of knowledge of it. Correct answers were given a score of one, and the total score for each subscale was used to describe the level of knowledge of it. Logistic regression was used to identify predictors of good knowledge about autism spectrum disorder (defined as a total score equal or above the mean score of the study participants). Results: This study enlisted the participation of 500 people. The participants’ overall understanding of autism spectrum disorder was moderate, with a mean score of 20.6 (SD: 5.6) out of 34, or 60.6 %. The participants’ knowledge levels ranged from 32.2 % to 77.5 %. The items about the abilities and needs of adolescents and young people with autism had the highest degree of knowledge (77.5 %). The items about autism's causes had the lowest level of expertise (32.2 %). When compared to others, females, those with a master’s degree, and those working in the healthcare field had a higher likelihood of knowing more about the autism spectrum condition. (p ≤ 0.05). Conclusion: Knowledge about autism spectrum disorder in Saudi Arabia is moderate. Social media channels and healthcare centers should be used to conduct educational campaigns for parents. The goal of this educational campaign should be to improve parents’ ability to recognize the causes of autism.