Cancer is not just a biological disease; it also impacts patients on psychological, social, and cultural levels. This chapter emphasizes that cancer patients often face challenges such as anxiety, depression, social isolation, and cultural stigma, which can worsen their mental health and hinder treatment adherence. By addressing cognitive distortions, enhancing social support, and respecting cultural beliefs, Cognitive Behavioral Therapy (CBT) helps patients manage their symptoms, reframe negative thoughts, and engage in meaningful activities. Cognitive restructuring, behavioral activation, and mindfulness are highlighted as effective interventions that improve patient’s quality of life and psychological resilience. The chapter also discusses the integration of culturally sensitive CBT and using assessment tools to tailor treatments to individual needs, underscoring the holistic approach necessary for cancer care. This chapter presents the foundational theory and model of CBT, followed by a detailed examination of its implementation in cancer care. A representative case study will also be provided, including case formulation and treatment planning.