This study aimed to compare the executive functions (EFs) and occupational performance and perceived occupational proficiency (POP) in children with neurodevelopmental disorders. In this study, 72 children diagnosed with cerebral palsy (CP; n = 22), specific learning disabilities (SpLD; n = 26) or attention deficit and hyperactivity disorder (ADHD; n = 24) were included in the study group and 84 typically developed children were included in the comparison group. All children were evaluated with the Child Occupational Self-Assessment (COSA) and all parents were evaluated with The Executive Function and Occupational Routines Scale (EFORTS) and the Canadian Occupational Performance Measure (COPM). Accordingly, statistically significant differences were found between the study group and the comparison group in terms of total scores of the COSA and EFORTS (p < 0.05). In addition, there was a significant difference between the CP, ADHD, and SpLD diagnosis groups and the comparison group in terms of sub-parameters of COSA and EFORTS score (p < 0.05). The findings showed that children with different diagnoses within neurodevelopmental disorders have difficulties in different EFs and occupational performance areas. Also, the pattern of association between EF and POP was different for each group. Therefore, therapists need to consider occupational performance and POP with EFs in their assessments before planning their intervention.