Background: Morbid obesity is the most severe condition among individuals with obesity and is associated with debilitating clinical complications and behavioral issues. However, the psychological processes underlying unhealthy behaviors in individuals with morbid obesity remains unexplored. There are few studies on the occurrence of distorted or dysfunctional cognitions amongst morbidly obese individuals, and even fewer studies comparing this with the occurrence of dysfunctional cognitions in lean individuals. Greater understanding of the psychological issues associated with morbid obesity could provide insights to help prevent and treat this complex and harmful condition. Objective: The aim of this study was to compare the occurrence of dysfunctional thinking processes, namely cognitive distortions and early maladaptive schemas, in people with morbid obesity versus people of normal weight. Methods: 111 participants – 53 morbidly obese and 58 of normal weight – were assessed with the Mini-Mental State Examination (MMSE), the Cognitive Distortions Questionnaire (CD-Quest), the Young Schema Questionnaire (YSW-S2), and the Depression, Anxiety and Stress Scale (DASS-21). Results: No significant differences were found between groups on cognitive distortions and early maladaptive schemas, except for the maladaptive schema of “insufficient self-control / self-discipline” which was more prevalent in the morbidly obese group compared to the group of normal weight. However, this failed to reach statistical significance when adjusted for levels of depression, anxiety and stress symptoms. Conclusion: There were no broad differences in regards to the levels of distorted or dysfunctional cognitions amongst morbidly obese versus lean individuals. Whilst “insufficient self-control / self-discipline” early maladaptive schemas may be more common amongst individuals with morbid obesity, this was confounded by symptoms of depression, anxiety and stress. These findings have potentially important implications for the treatment of morbidly obese individuals, disproving hypotheses that people with morbid obesity might have deep psychological problems associated with their excessive weight.