Means "glory", from the Portuguese and Spanish titles of the Virgin Mary Maria da Glória and María de Gloria. Maria da Glória (1819-1853) was the daughter of the Brazilian emperor Pedro I, eventually becoming queen of Portugal as Maria II.
The name was introduced to the English-speaking world by E. D. E. N. Southworth's novel 'Gloria' (1891) and George Bernard Shaw's play 'You Never Can Tell' (1898), which both feature characters with a Portuguese background. It was popularized in the early 20th century by American actress Gloria Swanson (1899-1983). Another famous bearer is feminist Gloria Steinem (1934-).