Cognitive theories assume that the content of our thoughts and beliefs, but also the way we approach them could be associated with the emergence of psychological disorders. The aim of this study was to investigate the role of dysfunctional attitudes and psychological inflexibility in explaining the symptoms of depression, anxiety and stress on a student sample. Research was conducted on a sample of 420 students from different faculties. Dysfunctional attitudes were assessed using The Dysfunctional Attitude Scale (DAS-A), while psychological inflexibility was assessed by Acceptance and Action Questionnaire (AAQ-II). Finally, symptoms of emotional disturbances were assessed by The Depression, Anxiety and Stress Scale (DASS-21). The results have shown that dysfunctional beliefs and psychological inflexibility have significant independent contribution in explaining the variance of emotional disturbances, even beyond contribution of demographic variables and current level of perceived stress that were included in the study as control variables. Elevations on scales of dysfunctional beliefs and psychological inflexibility were associated with more pronounced symptoms of depression, anxiety and stress. Psychological inflexibility has been shown to be the best predictor of depression, anxiety and stress symptoms. One of the explanations for such findings is that the way individuals respond to internal and external experiences is at least as equally important for maintaining emotional disorders as experiences per se.