'Donnerschlag' (i) was a German unrealised plan for the forces trapped in Stalingrad under the command of Generaloberst Friedrich Paulus to break out of their encirclement and link with a relief force (22/23 December 1942).

The trapped German forces were Paulus’s own 6^th Army and part of Generaloberst Hermann Hoth’s 4^th Panzerarmee, which were being pinned by the Soviet forces of General Andrei I. Eremenko’s Stalingrad Front, and the 'Donnerschlag' (i) plan was based on their advance in a south-westerly direction to meet the leading formations of Generalfeldmarschall Erich von Manstein’s Heeresgruppe 'Don' trying to break through to their relief in 'Wintergewitter' (i).

The plan was expressly vetoed by Adolf Hitler, who refused to consider even the possibility of a withdrawal from Stalingrad which, he insisted, was to be held an offensive fortress embedded in the Soviets' rear.