Claudio Achillini (Latin: Claudius Achillinus; 18 September 1574 – 1 October 1640[2]) was an Italian philosopher, theologian, mathematician, poet, and jurist.

As Jaynie Anderson has suggested,[5] Achillini may have devised the program for Agostino Carracci's frescoes in the Palazzo del Giardino.

Achillini was a particular friend of Giambattista Marino, whose style in poetry he imitated, occasionally lapsing into the excesses of extravagant metaphors.

[3] In the controversies that broke out after the publication of Marino's Adone (Paris, 1623), Achillini apparently encouraged Girolamo Aleandro to write his Difesa (1629) in response to Stigliani's attack on the poem in the Occhiale (1627).

A canzone, which he addressed to Louis XIII on the birth of the dauphin, is said to have been rewarded by Cardinal Richelieu with a gold chain or collar worth 1000 crowns;[4] this reward was not given, as some have asserted, for the famous sonnet Sudate o fuochi, a preparar metalli (Sweat, fires, in order to forge metal),[9] which was severely criticized by Manzoni.