Propranolol (INN) is a sympatholytic non-selective beta blocker. Sympatholytics are used to treat hypertension, anxiety and panic. It was the first successful beta blocker developed. Propranolol is available in generic form as propranolol hydrochloride, as well as an AstraZeneca and Wyeth product under the brand names Inderal, Inderal LA, Avlocardyl, Deralin, Dociton, Inderalici, InnoPran XL, Sumial, Anaprilinum, Bedranol SR (Sandoz).

Like other beta blockers, propranolol is a banned substance in several Olympic sports.

Scottish scientist James W. Black successfully developed propranolol in the 1960s. In 1988, he was awarded the Nobel Prize in Medicine for this discovery. Propranolol was derived from the early β-adrenergic antagonists dichloroisoprenaline and pronethalol. The key structural modification, which was carried through to essentially all subsequent beta blockers, was the insertion of an oxymethylene group into the arylethanolamine structure of pronethalol thus greatly increasing the potency of the compound. This also apparently eliminated the carcinogenicity found with pronethalol in animal models.