Count Adolf of Nassau-Siegen (8 August 1586 – 7 November 1608), German: Adolf Graf von Nassau-Siegen, official titles: Graf zu Nassau, Katzenelnbogen, Vianden und Diez, Herr zu Beilstein, was a count from the House of Nassau-Siegen, a cadet branch of the Ottonian Line of the House of Nassau.

Adolf was born at Dillenburg Castle on 8 August 1586[1] as the third son of Count John VII the Middle of Nassau-Siegen and his first wife, Countess Magdalene of Waldeck-Wildungen.

[2] He was baptised on Sunday 21 AugustJul..[3] Adolf studied in Geneva in 1601,[4] and then in Basel and in France.

In a letter of 8 December 1608 he even considered the death of Adolf as a punishment from God and he exhorted the two others, who with "einem ärgerlichen Leben mit Verschwendung fast allem, was ich in der Welt habe, durch Ehebrechen und Hurerei, Plünderung und Beraubung armer, unschuldiger Leute hoch und niederen Standen" ("an annoying life of squandering almost everything I have in the world, through adultery and fornication, plundering and robbing poor, innocent people of high and low rank") ruined the county of Nassau-Siegen, to lead a different, better life, worthy of the name Nassau.

van Schevichaven, a plaque measuring 103 by 64 cm was affixed to the northern transept of St. Stephen's Church in Nijmegen.