Art therapy intervention led by a psycho-oncologist in reducing anxiety and psychological distress in children with cancer is a complementary and interdisciplinary approach that aims to reduce the psychological burden of the disease, strengthen adaptation, and support the child's quality of life along with standard oncological treatments. The theoretical foundations of this intervention are based on the psychosocial biomodel, emotion regulation theories, child developmental approaches, and principles of psycho-oncology, and emphasizes the assumption that the experience of cancer is not limited to physical changes, but can also affect the child's sense of security, control, identity, social connection, and image of the future. Anxiety in children with cancer may be triggered or exacerbated in response to a diagnosis, hospitalization, separation from parents, hospital environment, aggressive actions, waiting for test results, pain, and complications of treatment. Psychological distress can also manifest in the form of fear, irritability, crying, withdrawal, sleep disturbances, decreased social participation, concentration problems, and behavioral changes. The psycho-oncologist assesses the level of distress and developmental characteristics of the child, and determines when, with what purpose, and with what intensity art therapy can be used. Through painting, coloring, collage, object making, illustration, storytelling, and age-appropriate creative activities, art therapy allows the child to express experiences that the child may or may not be able to express directly and verbally. In this process, the art product is not the subject of interpretation alone, but the process of creation, the child's choice, his interaction with the therapist, and the meaning that the child himself expresses for the work are important. One of the possible mechanisms of the effectiveness of art therapy is to facilitate emotion regulation, because the child can first identify difficult emotions through creative experience and then organize them in a visible and conversationable format. Artistic activity can also shift a child's attention from therapeutic anxiety-inducing situations to a structured and meaningful activity for a period of time. A sense of choice, control, and participation in the creation process may also be especially important in situations where the child is experiencing many decisions about his body and treatment under the supervision of others. The available research evidence on artistic and creative interventions in children with physical illnesses and cancer has shown that some art programs have been associated with reduced anxiety and distress and improved mood and participation, although the results of the studies are not the same in terms of type of intervention, number of sessions, age group, and measurement tools, and more controlled research is needed to determine the size of the definitive effect. In clinical application, the psycho-oncologist first examines the child's mental state using interviews, clinical observation, and standard tools, and then, together with the art therapist, sets specific goals, such as reducing anxiety, facilitating the expression of emotion, increasing feelings of control, or strengthening social connection. The choice of activity should be tailored to the child's age, cognitive ability, physical condition, interests, and therapeutic conditions. For young children, simple activities such as free painting, coloring, making fictional characters, and art games may be appropriate, while older children and adolescents may benefit more from the art office, illustrating the experience of illness, storytelling, photography, or the digital arts. When undergoing chemotherapy or other medical treatments, the intervention should be flexible and take into account the child's fatigue, nausea, pain, decreased energy, and physical limitations. The psycho-oncologist can also use art therapy to psychologically prepare the child before certain medical procedures, reduce tension after anxious actions, and strengthen the sense of security in the therapeutic environment. Parental involvement can also help strengthen emotional connection and create a positive shared experience, if the child is willing and ready. One of the important uses of this intervention is to help the child redefine the experience of the disease so that his identity is not limited to the "cancer patient" and the opportunity to experience creativity, play, connection, and personal empowerment is preserved. However, art therapy should not be presented as a substitute for medical treatment of cancer or independent treatment of severe psychological disorders, but should be implemented within the framework of comprehensive care and in coordination with the treatment team. An important suggestion in this regard is to design standard but flexible protocols in which the purpose of the intervention, the duration of the sessions, the type of activity, the evaluation indicators, and the criteria for discontinuation are clear. It is also recommended that the level of anxiety and distress be assessed before, during, and after the intervention with valid and age-appropriate tools so that the observed changes are not interpreted solely on the basis of the therapist's or parents' perceptions. Training art therapists in the field of pediatric cancer psychology, complications of treatment, principles of infection control, and communication with the medical team are also requirements for the safe implementation of these interventions. The most significant challenges are the wide differences in age, stage of development, type of cancer, physical condition, and family conditions of children, which limit the possibility of providing the same programme for all patients. Fatigue, pain, nausea, prolonged hospitalisation, and fluctuating physical condition may also reduce child participation. On the other hand, the available research evidence faces limitations such as small sample sizes, differences in intervention protocols, lack of long-term follow-up, and use of different tools. Therefore, future studies should be conducted with larger samples, appropriate control groups, standardized evaluations, and long-term follow-up to determine which components of art therapy are most beneficial and for which group of children. Overall, the guidance of art therapy by a psycho-oncologist can be part of a holistic model of psychosocial care in which reducing anxiety, managing distress, strengthening a sense of control, facilitating the expression of emotion, and maintaining the child's quality of life are considered alongside medical treatments.