Sir Thomas FitzAlan (died 1430) of Betchworth Castle in Surrey was a medieval English knight.
He was the 2nd son of John FitzAlan, 2nd Baron Arundel and Elizabeth le Despenser of Betchworth.
Thomas was Lord of Betchworth Castle, also known as Beechworth.
Sir Thomas married Joan Moyns, and they were parents of Eleanor FitzAlan.
Another descendant is the American Abolitionist, John Brown.