Mahoney v Ashton was a slavery case brought before the General Court of the Western Shore in Annapolis, Maryland in 1791.

On October 18, 1791, enslaved man Charles Mahoney filed a petition for freedom before the court against his owner, Father John Ashton, a Roman Catholic priest and former Jesuit.

Mahoney v. Ashton dragged on for twelve years, including three jury trials and two appeal hearings.

The result was inconclusive, but on the 4th of May 1804 John Ashton recorded a deed that "forever set free Charles Mahoney.

The case involved hundreds of participants including many notable members of the Maryland slave-owning gentry, including Charles Carroll of Carrollton.