Albert Frederick (German: Albrecht Friedrich, Polish: Albrecht Fryderyk) was Duke of Prussia from 1568 until his death. He was a son of Albert of Prussia and Anna Marie of Brunswick-Lüneburg. He was the second and last Prussian duke of the Ansbach branch of the Hohenzollern family.
As the great grandson of the Polish king Casimir IV Jagiellon, and as a Duke in Prussia who was fluent in Polish, Albert Frederick was seriously considered for a time as a possible candidate for the Polish throne. He particularly enjoyed the support of Polish Lutherans.
In 1572 he began to exhibit signs of mental disorder. In early 1578, the regency was taken over by his cousin, George Frederick of Brandenburg-Kulmbach (1539-1603). After George Frederick's death in 1603, the Polish king Sigismund III Vasa appointed Joachim Frederick as regent in 1605, and permitted his son, John Sigismund, to succeed him in 1611. The latter became Duke of Prussia after Albert Frederick's death in 1618.