Pedro Agustín Girón y de Las Casas, 1st Duke of Ahumada, 4th Marquis of the Amarillas (1778–1842) was a Spanish military officer and politician.

After Emperor Napoleon I of France invaded Spain and overthrew the monarchy, Girón offered his services to the patriotic forces, participating at the Battle of Bailén in July 1808, a major Spanish victory.

The Marquess of Wellington praised his allies' performance, writing that the Spanish attacked, "in as good order and with as much spirit as any that I have seen made by any troops."

[4] Girón also led the two divisions, with 7,653 soldiers in all, at the Battle of Nivelle on 10 November, where his troops helped take the fortified village of Sare.

His son, Francisco Javier Girón y Ezpeleta, 2nd Duke of Ahumada and 5th Marquis of the Amarillas, founded the Spanish Guardia Civil in 1844.