'Herbstnebel' (ii) was a German unrealised plan by Generalfeldmarschall Walter Model’s Heeresgruppe 'B' for an offensive, not intended to advance farther to the west than the Meuse river, against the Western Allies at the end of 1944 (27 October 1944).

This operation was schemed as an alternative to 'Martin' (ii) devised by the staff of Generalfeldmarschall Gerd von Rundstedt, the Oberbefehlshaber 'West', for the major offensive desired by Adolf Hitler to break the momentum of the Western Allies' advance into western Germany. 'Martin' (ii) was preferred to 'Herbstnebel' (ii), and was then developed and implemented as 'Wacht am Rhein'.