PURPOSE: Peritraumatic reactions play a crucial role in the development of mental health problems, including depression and post-traumatic stress disorder. Therefore, this study sought to examine the influence of the peritraumatic reactions, including peritraumatic dissociation, peritraumatic distress, mental defeat, and tonic immobility, on post-traumatic stress disorder and major depressive disorder in earthquake survivors. MATERIALS AND METHODS: A total of 261 adult participants aged between 18 and 65 (M=29.20, SD = 28.06, 162 were female, and 99 were male) who were exposed to the Kahramanmaras earthquake in February 2023 were recruited in the study. Data were collected between April 10 and 18 2023, two months after the earthquake. Participants completed questionnaires, including The International Trauma Questionnaire, The International Depression Questionnaire, The Mental Defeat Questionnaire, The Tonic Immobility Scale, and The Peritraumatic Dissociative Experiences Questionnaire. RESULTS: Two-step multiple linear regression analyses indicated all peritraumatic reactions predicted both post-traumatic stress disorder and depression. Dominance analysis results showed that the contribution of peritraumatic dissociation in predicting PTSD and depression was higher among other peritraumatic reactions. CONCLUSION: The findings of the study revealed a robust association between peritraumatic reactions and both depression and PTSD, shedding light on the underlying processes in the development of trauma-related disorders. Early assessment of peritraumatic reactions may be useful in identifying individuals at risk of developing PTSD and depression.