Abstract Introduction and Objectives: Covid-19 pandemic in 2020 and the use of quarantine to prevent it have increased psychological reactions like depression, anxiety and stress in the general population. Hence, the need to identify variables that can affect these psychological reactions is felt more than ever. The aim of this study was to predict the rate of depression, stress and anxiety during quarantine based on psychological flexibility, dysfunctional attitude and coping styles. Method The research design was descriptive-correlational and the statistical population included all students who were active in the social media. A total of 501 students accessed the call for completion of questionnaires on online media, including Instagram, completed prepared questionnaires in the Google Form format. Measures included the Depression, Anxiety, and Stress Questionnaire (DASS-21, 1995), the Revised Dysfunctional Attitude Scale (DAS-26, 1978), the Acceptance and Practice Questionnaire (AAQ-II, 2005), and the Lazarus and Folkman Coping Strategies Questionnaire (CSQ, 1984). Results Psychological inflexibility, dysfunctional attitudes, and maladaptive coping strategies predicted depression, anxiety, and stress in a positive way, but problem-oriented coping strategies only showed an inverse relationship with depression. In regression analyzes, the variable of psychological inflexibility had the greatest effect on explaining depression, anxiety and stress. Discussion and Conclusion It can be concluded that teaching psychological flexibility and cognitive reconstruction can be useful in reducing depression, anxiety, and stress during the quarantine. Teaching problem-solving strategies can also have positive effects on reducing depression.