Abstract: Temporomandibular disorders (TMDs) represent a group of musculoskeletal and neuromuscular conditions affecting the temporomandibular joint, masticatory muscles, and associated structures, often presenting with chronic pain, functional limitation, and psychological distress. Emerging evidence highlights the pivotal role of stress as a precipitating and perpetuating factor in TMD, mediated largely through neuroendocrine mechanisms. The hypothalamic–pituitary–adrenal (HPA) axis, a central component of the body’s stress response system, plays a crucial role in maintaining homeostasis during acute stress but may contribute to pathological outcomes when dysregulated. Chronic activation or maladaptation of the HPA axis has been implicated in altered cortisol secretion, neuroinflammation, pain sensitization, and impaired coping mechanisms, all of which are relevant to stress-induced TMD. This review critically examines the relationship between HPA axis dysregulation and stress-related TMD, integrating current evidence from neurobiology, psychoneuroendocrinology, and pain research. Additionally, it emphasizes the vital role of nurses in early identification, holistic assessment, stress management, patient education, and multidisciplinary coordination. Understanding the neuroendocrine underpinnings of TMD provides a framework for nursing professionals to implement evidence-based, patient-centered interventions aimed at reducing symptom burden, improving quality of life, and preventing chronicity.