Psychological stress is considered one of the most significant challenges that humans face in daily life, especially with the fast pace of modern living and increasing responsibilities. Its effects are not limited to mood or mental health only, but extend to overall physical health, particularly the immune system. First: What is the immune system? The immune system is the body’s primary defense mechanism. It protects the body from diseases and infections by identifying and attacking harmful agents such as viruses and bacteria. Second: How does psychological stress affect the immune system? When a person is exposed to psychological stress, the body releases hormones such as cortisol and adrenaline. Although these hormones help the body respond to emergency situations, prolonged secretion leads to negative effects, including: Weakened immune response: Chronic stress reduces the efficiency of immune cells, making the body more vulnerable to diseases. Increased inflammation: Continuous stress can trigger inflammation in the body, which may be linked to chronic illnesses. Slower wound healing: Individuals under stress may notice that their wounds take longer to heal. Higher susceptibility to infections: Such as colds and influenza, due to reduced immune efficiency. Third: Long-term effects Prolonged psychological stress can lead to more serious health problems such as heart disease, diabetes, and autoimmune disorders, where the immune system begins to attack the body’s own cells. Fourth: Ways to reduce the impact of stress To maintain a strong immune system, it is important to manage stress through: Regular physical exercise Getting enough sleep Following a healthy diet Practicing relaxation techniques such as meditation and deep breathing Managing time effectively and avoiding overload Conclusion The relationship between psychological stress and the immune system is very strong, as stress can directly affect the body’s ability to resist diseases. Therefore, mental health care is just as important as physical health care, and it plays a key role in improving overall quality of life. Prepared by: Lecturer: Huda Rafid Abdul Khaleq AL_mustaqbal University is the first university in Iraq