Background: Children with autism spectrum disorder (ASD) face some challenges with performing self-care. Many performance components, including sensory and cognitive functions, are effective in performing self-care. Objectives: This study aimed to compare the role of sensory processing and executive functions in performing self-care among preschool children with ASD. Methods: In this cross-sectional study, 70 children with ASD aged 3-6 years were selected and investigated by adopting convenience sampling. The instruments included the Short Sensory Profile-2 (SSP-2), Behavior Rating Inventory of Executive Function (BRIEF), and Pediatric Evaluation of Disability Inventory (PEDI). The data were analyzed using Pearson correlation and linear regression tests. Results: The results of the correlation revealed that executive functions (P≤0.01) and sensory processing (P ≤ 0.005) had a small yet significant inverse relationship with performing self-care activities. The results of stepwise linear regression showed that executive functions and sensory processing were equally capable of predicting self-care activities. Conclusions: It was recommended that therapists should pay enough attention to both executive functions and sensory processing in order to solve the self-care problems of preschool children with ASD. Due to the low correlation between variables, it was also suggested that a multifactorial approach to self-care activities should be employed as well as the role of other factors along with sensory processing and executive function should be considered.