This study aimed to examine the associations between Cognitive Disengagement Syndrome (CDS) and Specific Learning Disorder (SLD) in children and adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD). We included sixty “ADHD-only” cases and eighty-two “ADHD + SLD” cases with an IQ score of 80 and above, aged 8-15. We applied both a structured psychiatric interview and a mental status examination. Parents completed the ADHD-Rating Scale IV, Barkley Child Attention Scale, and Specific Learning Disorder-Evaluation Scale. The sample consisted of 94 boys and 48 girls. The mean age of the cases was 10,90 ± 2,32. The “ADHD + SLD” group had a higher proportion of cases with CDS than the “ADHD-only” group (47,6% vs 15%). The “ADHD + SLD” group had significantly higher CDS-total, CDS-sluggish, and CDS-daydreaming scores than the “ADHD-only” group. SLD score was positively associated with CDS-total, CDS-sluggish, and CDS-daydreaming scores. Even when controlled for inattentive symptoms, IQ, drug treatment duration, socioeconomic level, and parental education level, CDS-daydreaming scores but not CDS-sluggish scores were associated with higher SLD scores. The findings indicate a prominent association between CDS and SLD. CDS symptoms -mainly- CDS-daydreaming symptoms are essentially associated with SLD even when controlled for inattentive symptoms, IQ, drug treatment duration, and relevant demographic factors. Therefore, clinicians should pay attention to a possible coexistence of CDS while evaluating cases with SLD.