The role of the psycho-oncologist in managing the psychological crisis of the family after the diagnosis of malignancy is one of the most sensitive areas of intervention in psycho-oncology, because the announcement of a cancer diagnosis can suddenly disrupt the psychological balance and the usual structure of family life. The word malignancy is associated with concepts such as life threats, fear of death, uncertainty, changing the future, and worrying about loss, and may trigger reactions such as shock, disbelief, intense anxiety, crying, anger, denial, helplessness, sleep disturbances, and difficulty in making decisions. The psycho-oncologist is tasked with assessing the severity of the mental crisis first and foremost to distinguish between the normal and expected reaction to the news of the cancer and severe or debilitating distress. The initial assessment can include the emotional state of the patient and family members, the level of social support, the history of psychological problems, the quality of family relationships, the financial situation, and the family's ability to continue functioning on a daily basis. One of the most important roles of a psycho-oncologist is to create a safe and non-judgmental environment so that family members can express their fears and concerns and do not have to play the role of a strong and calm person in front of the patient at all times. Psychological education is important in the crisis phase, as the family may relate any physical symptom or any medical information to the most severe possible outcome. Providing clear psychological information about natural responses to a crisis can help the family better understand their experience. A psycho-oncologist can also help the family receive and organize information about diagnosis and treatment in an understandable way, as receiving large amounts of information in a traumatic situation may reduce cognitive processing capacity. Anxiety management is another important focus of intervention and can include breathing techniques, relaxation, mindfulness attention, and emotion regulation. Along with these methods, cognitive interventions can address catastrophic thoughts, such as a definite perception of death or a belief in the family's total incapacity. The goal of these interventions is not to create unrealistic hope, but rather to help the family separate medical realities from fears and predictions caused by the crisis. During the diagnosis phase, some families may refuse to talk about cancer for fear of upsetting the patient, and this silence can lead to increased mutual anxiety. By teaching empathic communication, a psycho-oncologist can help the family have a constructive conversation about their needs, concerns, and preferences. Respect for the patient's autonomy is also important at this stage, and the family must distinguish between supporting the patient and making decisions on their behalf. In families where members react differently to the diagnosis, the psycho-oncologist should consider these differences to be normal and avoid imposing a single pattern of exposure to the disease. One member may seek more information, another may need emotional support, and the other person may prefer to take a break from talking about the illness for a while. Managing these differences can prevent conflict and blame in the family. Another important task of a psycho-oncologist is to identify the person or people who are likely to bear the main burden of care. Sharing responsibilities from the very early stages can prevent the pressure from focusing on a caregiver. In families with children, the explanation of the illness should be appropriate for the child's age and cognitive ability, as the child's complete exclusion from information may increase anxiety caused by ambiguity. A psycho-oncologist can teach parents how to provide the child with accurate and understandable information without creating additional fear. Supporting the family's social network is also important during the crisis phase, as a family that has the support of relatives, friends, or social resources may have a greater capacity to cope with initial stress. Family-centered interventions can help activate these resources and prevent social isolation. In the event of severe symptoms of anxiety, depression, dysfunction, or thoughts of self-harm, a more specialized assessment and immediate referral are necessary, and the psycho-oncologist should act in coordination with the relevant professionals. In some families, spiritual beliefs and personal values can also be a source of coping, and if the family wishes, these resources can be taken into account in the process of psychological support. Art therapy, narrative therapy, and other creative methods can also be used in later stages as complementary interventions to express emotions and reconstruct the experience of diagnosis. Over time, the initial crisis may turn into concerns about treatment, complications, costs, the future, and the possibility of recurrence, so the management of the psychological crisis should not be limited to the first days of diagnosis. The psycho-oncologist should reassess the family's situation at different stages of the disease course and continue the intervention as the situation changes. One of the major challenges in this area is the high psychological pressure of the family and the decrease in decision-making capacity in the first hours and days after diagnosis, so interventions should be gradual, clear, and commensurate with the family's processing capacity. Also, the family's natural reaction to the news of malignancy should not be interpreted as a mental disorder immediately, because fear and grief in such situations are not necessarily a symptom of mental illness. Overall, a psycho-oncologist helps the family move from the stage of initial shock and instability to gradual adjustment and psychosocial organization by assessing distress, establishing psychological security, educating, regulating emotion, strengthening family relationships, facilitating informed participation, supporting caregivers, and identifying cases requiring specialized referrals. The main goal of this intervention is not to completely eliminate fear and grief, but to create the psychological capacity necessary to face the course of the disease more consciously and tolerably.