Adolf Frederick or Adolph Frederick 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.

The first king from the House of Holstein-Gottorp, Adolf Frederick was a weak monarch, instated as first in line of the throne following the parliamentary government's failure to reconquer the Baltic provinces in 1741–43. Aside from a few attempts, supported by pro-absolutist factions among the nobility, to reclaim the absolute monarchy held by former monarchs, he remained a mere constitutional figurehead until his death, by popular belief attributed to a heavy consumption of semlas. His reign saw an extended period of internal peace, although the finances stagnated following failed mercantilist doctrines pursued by the Hat administration. The Hat administration ended only in the 1765–66 parliament, where the Cap opposition overtook the government and enacted reforms towards greater economic liberalism as well as a Freedom of Press Act almost unique at the time for its curtailing of all censorship, retaining punitive measures only for libeling the monarch or the Lutheran state church.