Samuel Aba (Hungarian: Aba Sámuel; before 990 or c. 1009 – 5 July 1044) was the third King of Hungary between 1041 and 1044.

He was born to a prominent family with extensive domains in the region of the Mátra Hills.

He or his father marries a sister of Stephen I, the first King of Hungary, around 1009.

The king appoints Samuel to head the royal court as his palatine.

King Stephen dies in 1038, and the new monarch, Peter the Venetian, removes Samuel from his post.

However, the Hungarian lords dethrone Peter in 1041 and elect Samuel king.

In 1044, Peter the Venetian returns with the assistance of Henry III, Holy Roman Emperor, and defeats Samuel's army at the battle of Ménfő.

Samuel flees from the battlefield, but is captured and killed.