Hyperthyroidism can be classified into overt or subclinical forms and may occur with or without thyrotoxicosis. Common causes include Graves’ disease, nodular thyroid disease, and Hashitoxicosis, among others. The excess of thyroid hormones leads to a broad spectrum of symptoms and signs, which may be general or organ-specific. If left untreated, it can result in various complications involving the cardiovascular system, osteoporosis, thyrotoxic periodic paralysis, and thyroid storm. Investigations include serum thyroid-stimulating hormone (TSH), serum T4 and T3, TSH receptor antibodies, ultrasonography of the thyroid gland, and the radioactive iodine uptake test. All patients should have serum TSH, T3, and T4 measured, with further evaluation guided by the suspected underlying cause. The choice of management depends on the underlying cause, likelihood of remission, and patient-specific risk factors. Antithyroid medications and beta-blockers are the mainstays of treatment, with radioactive iodine therapy and thyroidectomy considered in selected cases. Patients with subclinical hyperthyroidism should be carefully assessed, and treatment initiated based on age, symptomatology, risk factors, and investigation results. Patients must be counselled appropriately regarding their condition, treatment options, and the need for long-term monitoring and follow-up.