Effective postoperative pain management is central to enhanced recovery, patient satisfaction, and the reduction of complications. Poorly controlled pain contributes to impaired mobilization, pulmonary complications (e.g., atelectasis and pneumonia), delirium, and persistent post-surgical pain syndromes. Optimal management requires balancing analgesic efficacy with the minimization of opioid-related adverse effects and long-term dependence. Contemporary approaches emphasize multimodal analgesia, employing agents with complementary mechanisms such as acetaminophen, non steroidal anti inflammatory drugs (NSAIDs), gabapentinoids, ketamine, dexmedetomidine, and regional anesthesia techniques. Rescue regional anesthesia techniques, including single-shot and catheter-based peripheral nerve or neuraxial blocks, offer opioid-sparing analgesia and can be lifesaving in managing severe postoperative pain crises. Special populations present unique challenges. Patients maintained on buprenorphine or methadone require careful perioperative planning to ensure adequate analgesia. Those using illicit opioids present with tolerance, unpredictable pharmacokinetics, and increased risk of withdrawal. Coordination with acute pain services, addiction medicine, and psychiatry is essential to providing patient-centered, comprehensive care. Opioid stewardship seeks to minimize unnecessary exposure, prevent persistent use, and tailor prescriptions to expected needs while ensuring adequate pain relief. This includes limiting discharge opioid quantities, employing multimodal regimens, and patient education. This chapter reviews principles of postoperative pain management, including pharmacologic and regional approaches, strategies for patients with chronic opioid therapy or opioid use disorder, and the importance of stewardship programs in mitigating the opioid epidemic.