Francesco Caetani, 8th Duke of Sermoneta

Francesco Caetani, 8th Duke of Sermoneta, (11 March 1594 – 9 October 1683) was an Italian nobleman in the service of the King of Spain.

Aged 15, he came to Spain with his uncle, cardinal Antonio Caetani (iuniore), where he was a royal page.

In 1617 he became a Grandee of Spain and returned to his estates in Italy, which were in serious financial problems.

After the death of his first wife Anna Acquaviva d'Aragona in 1659, he was engaged and later married Leonor Pimentel Moscoso y Toledo, daughter of Antonio Pimentel Enríquez de Guzmán y Toledo.

The support of his future wife and her influential family played a decisive role in Caetani's career.