Background: According to DSM-5, sensory processing problems are among diagnostic criteria in children with autism spectrum disorder (ASD). Various studies have shown that games, as the main occupation of children, can be helpful in performing sensory interventions. Solving sensory problems is one of the most common demands of families with children with ASD. Children's families play a key role in the implementation of occupational therapeutic interventions. Objectives: This randomized clinical trial investigated the effectiveness of sensory play activities performed by parents at home on the sensory patterns of children with ASD. Methods: Fifty-one children with ASD, aged 3 to 6 years, were divided into the intervention and control groups. All participants attended 16 sessions of in-person individualized sensory integration therapy (SIT) in a clinic for 8 weeks. In the intervention group, children received 8 sessions of a sensory play activity intervention performed by parents at home. Data collection instruments included the Gilliam Autism Rating Scale-2 and the sensory profile 2. Parametric (independent and paired t-test) and non-parametric (Mann-Whitney and Wilcoxon tests) were used for statistical analysis to compare between-group and within-group mean differences. Results: The results showed that although all four sensory processing patterns improved significantly in both groups (P < 0.05) (i.e., the within-group effect), children in the intervention group showed significant improvements in three sensory patterns, including sensory avoiding, sensory sensitivity, and sensory registration (P< 0.01). There was no significant difference in the mean score of the sensory seeking pattern between the 2 groups (P > 0.05). Conclusions: Sensory integration therapy improved dysfunctional sensory processing patterns in ASD children, an effect that was enhanced by the simultaneous implementation of sensory play interventions.