Has a sequel ever won Best Picture at the Academy Awards?

As of 2015, "The Godfather, Part II" and "The Lord of the Rings: The Return of the King" are sequels that won an Academy Award for Best Picture. All films in "The Godfather" and "The Lord of the Rings" trilogies were nominated for Best Picture.

The first sequel nominated for Best Picture was "The Bells of St. Mary's." While "The Silence of the Lambs" was technically a sequel from a plot standpoint, a completely separate production company, studio and cast were involved in the film's production. "The Lord of the Rings: The Return of the King" is the only third part of a series to win Best Picture.