'Frühlingssturm' was a German and Croat operation against the partisan forces of Marshal Josip Broz Tito along the Danube river in the puppet state of Croatia in German-occupied Yugoslavia (17/21 January 1945).

The objective of this major undertaking by General Helmuth Felmy’s XXXIV Corps zbV in Syrmia was the relief of the pressure on General Maximilian de Angelis’s 2^nd Panzerarmee along the Danube river farther to the north. The partisan forces involved were the 1^st, 2^nd and 6^th Proletarian Divisions and the 5^th and 21^st Divisions, all supported by Soviet artillery and aircraft. The Axis forces were based on SS-Brigadeführer und Generalmajor der Waffen-SS Otto Kumm’s 7^th SS Gebirgsdivision 'Prinz Eugen', Generalleutnant Kohler’s 11^th Felddivision (L), Generalleutnant Wolfgang Hauser’s 41^st Division, Generalleutnant August Wittmann’s 117^th Jägerdivision and, as the Croat contribution, General Stjepan Mifek’s 3^rd Division.

The Germans advanced to the south-east against extensive and well-dug trench lines and fortified positions manned by large numbers of partisans. By the end of the operation’s first day the 7^th SS Gebirgsdivision and other units had driven some 5 miles (8 km) deep into the positions held by the partisans, who were therefore forced to start bringing up reinforcements. The momentum of the Axis advance was maintained, and by the end of 'Frühlingssturm' the Germans had retaken the key highway hub of Sid and were stretched out between there and Sarengrad, a small village on the Danube.

The operation was considered a success because some of the pressure was taken off the 2^nd Panzerarmee. No complete loss figures are known, but the XXXIV Corps reported it had killed 12,000 partisans.