Adolf Hermann Wilhelm Hagen (23 September 1820 – 17 August 1894) was a public official in Prussia. He was also a banker and a liberal politician. He is known for the "Hagen resolution", presented in the Prussian House of Representatives in 1862, which triggered a general election and heralded the end of the so-called (and as matters turned out short-lived) "New Era" in Prussian politics.