Adolf of Nassau (ca. 1255 - July 2, 1298) was King of the Romans from 1292 until 1298.

Adolf of Nassau was a member of the minor nobility, born about 1255 as son of count Walram II of Nassau and his wife, formerly Adelheid von Katzenelnbogen.

He had neither influence nor power, and was elected to become Holy Roman Emperor because of the electors' preference for a weak emperor. His election was largely secured through the influence of the elector-archbishops of Mainz and Cologne. He was crowned King of the Romans (Emperor-Elect) on June 2, 1292, at Aachen. He was never crowned by the pope in Rome, which would have secured him the title of Emperor.

He married Imagina von Limburg an der Lahn; they had eight children, among them Mechthild (who married Rudolf I "der Stammler", Duke of Upper-Bavaria), Rupert, Adolf and Gerlach I, who would succeed his father as count of Nassau-Wiesbaden-Idstein.

He founded the convent of Clarenthal near Wiesbaden in 1296.

His pursuit of territorial claims in Thüringen turned his supporters against him, and they elected Albrecht von Habsburg in his place in 1298. Adolf refused to accept this decision but was killed in the battle of Göllnheim (near Speyer) against Albrecht on July 2, 1298.

"A stalwart but necessitous Herr" Carlyle calls him. He seems to have been under the pay of Edward Longshanks.