Attention-deficit/hyperactivity disorder (ADHD), characterized by diagnostic complexity and symptom heterogeneity, is a prevalent neurodevelopmental disorder. In this study, we explored the machine learning analysis of retinal fundus photographs as a novel, noninvasive biomarker for ADHD screening and stratification of executive function (EF) deficits. Children and adolescents (<19 years) with ADHD (n=323) were recruited from two tertiary South Korean hospitals between April and October 2022. Retinal photographs of age- and sex-matched individuals with typical development were retrospectively collected. Individuals with major psychiatric disorders, neurological illnesses, and eye diseases affecting the retinal fundus were excluded. Retinal features were extracted using AutoMorph. Machine learning models for ADHD screening and EF subdomain prediction were developed using the comprehensive attention test. Model performance was evaluated via five-fold cross-validation with metrics including the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity. Feature importance was assessed using the Shapely additive explanation method. We analyzed 1,108 fundus photographs from 648 participants (mean age 9.5 years, 77.1% boys). ADHD screening models achieved 0.955–0.969 AUROC values, with vessel density as the most important feature. For EF function stratification, the visual and auditory subdomains showed strong (AUROC >0.85) and poor performances, respectively. Machine learning analysis of retinal fundus photographs demonstrated potential as a noninvasive biomarker for ADHD screening and EF deficit stratification in the visual attention domain. Furthermore, alterations in the retinal vascular structure and optic disc characteristics indicate a neurodevelopmental process affecting both cerebral and retinal structures, potentially reflecting systemic changes in ADHD. Our findings may guide the development of innovative screening tools and personalized treatment approaches. However, further research across diverse populations and age groups is necessary to validate these findings before clinical implementation.