Adolf Frederick (Adolf Fredrik) (14 May 1710 – 12 February 1771) was King of Sweden from 1751 until his death. He was the son of Christian August of Holstein-Gottorp, Prince of Eutin and Albertina Frederica of Baden-Durlach.
On his mother's side, Adolf Frederick descended from king Gustav I of Sweden and from a sister of Charles X of Sweden. From both his parents he was descended from Holstein-Gottorp, a house with a number of medieval Scandinavian royal dynasties among its ancestors. Adolf Frederick was also a 13th-generation descendant of Erik V of Denmark; a 13th-generation descendant of Sophia of Denmark and Valdemar I of Sweden; and an 11th-generation descendant of Euphemia of Sweden, Duchess of Mecklenburg and her husband the duke Albrecht.
During his whole reign (1751-1771), Adolf Frederick was little more than a state decoration, the real power being lodged in the hands of an omnipotent riksdag, distracted by fierce party strife. Twice he endeavoured to free himself from the intolerable tutelage of the estates. The first occasion was in 1755 when, stimulated by his imperious consort Louisa Ulrika of Prussia (1720-82), sister of Frederick the Great, he tried to regain a portion of the attenuated prerogative, and nearly lost his throne in consequence. On the second occasion, under the guidance of his eldest son, the crown prince Gustavus, afterwards Gustav III of Sweden, he succeeded in overthrowing the tyrannous "Cap" senate, but was unable to make any use of his victory.
His mother, a widow princess, died in Hamburg on December 22, 1755. She was a descendant of earlier royal dynasties of Sweden, granddaughter of Christina Magdalena of Palatinate, Charles X's sister.
He was regarded, both during his time and in later times, as dependent on others, a weak ruler and lacking of any talents. But he was allegedly also a good husband, a caring father and a gentle master to his servants. His favourite pastime was to make snuff boxes, which he allegedly spent a great deal of time doing. His personal hospitality and friendliness were witnessed by many who deeply mourned him at his death.
His portrait is included with the 16-sheet series of Princely Persons on Horseback by Johann Elias Ridinger.