This study aimed to identify the level of irrational beliefs among mothers of children with Down syndrome in the Libyan context, to uncover the most common of these beliefs, and to examine differences in the adoption of these beliefs according to certain demographic variables related to the mother (age, educational level, marital status) and the child (age, gender). The study employed a descriptive exploratory approach, and the Irrational Beliefs Scale was administered to a purposive sample of (25) mothers affiliated with the Asaria Organization for People with Disabilities in the city of Zawiya. The results showed a relatively high level of irrational beliefs among the mothers, with variations in the degree of prevalence of these beliefs across the different items. The study revealed that the most common irrational thoughts were an intense fear of the child being exposed to danger. The results indicated no statistically significant differences in the adoption of irrational thoughts attributable to the mother's age, educational level, or social status, as well as the child's age and gender. This suggests that these thoughts are more closely linked to the nature of the psychological pressures and shared experiences of the mothers. The study underscores the importance of counseling interventions, particularly programs based on Rational Emotive Behavior Therapy (REBT), in modifying irrational thoughts among mothers, thereby contributing to improved mental health and enhancing their ability to cope with the demands of caring for their children.......... Keywords:...... Irrational thoughts, Down syndrome, mothers of children with disabilities, psychological adjustment, Rational Emotive Behavior Therapy