This learning activity examines thyroid disorders across the lifespan, covering pathophysiology, diagnostic interpretation, and evidence-based nursing management for adolescent, adult, and older adult patients. Topics include thyroid function testing, nodule risk stratification, pharmacologic considerations, and lifespan-specific clinical presentations, with reference to current ATA guidelines and emerging therapies. Emphasis is placed on the nurse's role in patient education, medication safety, interprofessional collaboration, and translating evolving evidence into individualized, patient-centered care.