Betamethasone is a potent synthetic glucocorticoid steroid widely used for its anti-inflammatory, immunosuppressive, and anti-allergic effects, treating conditions such as asthma, autoimmune disorders, allergic reactions, and skin diseases. It works by binding to glucocorticoid receptors, regulating gene expression, and suppressing inflammatory mediators, and is available in oral, injectable, topical, and inhaled forms. Developed in the 1950s as a fluorinated derivative of prednisolone, betamethasone was designed to enhance anti-inflammatory activity while minimizing sodium-retaining effects. Over the decades, it has become a cornerstone in both human and veterinary medicine, with applications in dermatology, rheumatology, and obstetrics, including prevention of preterm labor complications. Its inclusion in the World Health Organization’s List of Essential Medicines highlights its global significance, and ongoing research continues to explore its therapeutic potential and safety profile.