Background: Psychiatric disorders are becoming a serious public health concern. Long term caregiving responsibilities to psychiatric patients can decrease resources of the families, energy, making them fatigued and more vulnerable to adverse emotions as a feeling of hopeless or, depression, despair and a notable decline in in their psychological adjustment. The present study aims to investigate the relation between positive thinking and psychological adjustment among psychiatric patients' caregivers. Design: A descriptive correlational research design was utilized. Setting: The study was conducted in the psychiatric outpatient clinic at Port Said Psychiatric Health Hospital and Addiction Treatment. Subjects: A purposive sample of 66 psychiatric patients' caregivers. Tools: Two tools were used for data collection:  Tool I: The Positive Thinking Scale, Tool II: The Psychological Adjustment Scale, in addition to the Personal and Clinical Data Sheet of the studied psychiatric patients' caregivers. The Results: The majority of the studied psychiatric patients' caregivers had a lower degree of positive thinking, as well as, a low level of psychological adjustment. Conclusion: There was a highly statistically ‎significant positive correlation between the total score of positive thinking and the total score of psychological adjustment among psychiatric patients' caregivers. Recommendations: The study recommended that providing ongoing support and adequate guidance, such as support groups or counseling services, can help the family caregivers to maintain a positive mindset and cope with the challenges they face. As well as, application of positive thinking skills training program to enhance the psychological adjustment among psychiatric patients' caregivers.