Gaetano Polidori (1764–1853) was an Italian writer and scholar living in London. He was the son of Agostino Ansano Polidori (1714–78), a physician and poet who lived and practised in his native Bientina, near Pisa, Tuscany.
Polidori studied law at the University of Pisa. He became secretary to the tragedian Vittorio Alfieri in 1785 and remained with him four years.
He came to England from Paris in 1790 after resigning as Alfieri's secretary. He settled in London, working as an Italian teacher.
He translated various literary works into Italian, notably, John Milton's Paradise Lost and Horace Walpole's The Castle of Otranto, as well as other writings of Milton and Lucan. He wrote prolifically, producing his own fiction, poetry, criticism, and tragedies.
In 1793, he married an English governess, Anna Maria Pierce, and they had four sons and four daughters. His oldest son John William Polidori was a physician to Lord Byron and author of the first vampire story in English, The Vampyre (1819).
His daughter Frances Polidori married exiled Italian scholar Gabriele Rossetti and had four children, Maria Francesca Rossetti, Dante Gabriel Rossetti, William Michael Rossetti and Christina Georgina Rossetti.