Purpose <p>This cross-sectional case-control study explored associations between dietary patterns, inflammatory biomarkers, and behavioral symptoms in children with autism spectrum disorder (ASD).</p> Methods <p>We recruited 40 children with ASD and 57 with typical development (TD). Dietary patterns were derived using exploratory factor analysis from a food frequency questionnaire. Behavioral measures included the Social Responsiveness Scale, Repetitive Behavior Questionnaire-2, and Short Sensory Profile. Inflammatory markers were analyzed via multiplex immunoassay and ELISA.</p> Results <p>Two dietary patterns were identified: “Factor 1: Processed Foods and Sweets Pattern” and “Factor 2: Plant- and Grain-Based Pattern”. Children with ASD scored significantly lower on the factor 2 than TD children (<i>p</i> = 0.006). Within the ASD group, higher factor 2 scores were negatively correlated with social motivation deficits, autistic mannerisms, and total scores on the SRS and RBQ-2, and positively correlated with auditory filtering and the SSP total score. Children with ASD exhibited elevated inflammatory markers, with EGF specifically higher in those adhering to the Processed Foods and Sweets Pattern. An exploratory ROC analysis revealed that SRS and RBQ-2 total scores could distinguish adherence to the Plant- and Grain-Based Pattern in ASD group (AUCs = 0.817, 0.746).</p> Conclusion <p>These exploratory findings highlight links between dietary patterns and ASD symptoms, sensory processing, and inflammatory status. The Plant- and Grain-Based Pattern may serve a protective role, while an Processed Foods and Sweets Pattern may exacerbate inflammation. Further longitudinal and interventional studies are needed to confirm these cross-sectional associations.</p>