The 'Nagykanizsa-Körmend Offensive Operation' was a Soviet operation by Marshal Sovetskogo Soyuza Fyedor I. Tolbukhin’s 3^rd Ukrainian Front during its 'Vienna Strategic Offensive Operation' against the German, Croat and Hungarian forces of General Otto Wöhler’s Heeresgruppe 'Süd' attempting to hold the defensive line linking Kisbajom, Nagykorpád, Nagyatád and Heresznye to the north of the Drava river and west of Lake Balaton (26 March/15 April 1945).

The objective of the operation, which was one of the five elements of the 'Vienna Strategic Offensive Operation' (the 'Győr Offensive Operation' of 13 March/4 April, the 'Veszprem Offensive Operation of 16/25 March, the 'Sopron-Baden Offensive Operation' of 26 March/4 April, the 'Nagykanizsa-Körmend Offensive Operation' of 26 March/15 April and the 'Assault on Vienna Operation' of 4/13 April), was to cut all Axis access to the oil wells and fuel-processing facilities in the Nagykanizsa region of Hungary in the area to the west of Lake Balaton. These facilities were deemed vital to the continued German war effort, and their protection had led Heeresgruppe 'Süd' to construct three defensive lines behind the natural water obstacle of the Mura river and linked to the western shore of Lake Balaton.

The bulk of the Soviet forces for the operation comprised General Polkovnik Vladimir D. Stoychev’s Bulgarian 1^st Army with two corps comprising six infantry divisions and a number of smaller units, totalling about 100,000 men in all. This army advanced on the southern flank of the 3^rd Ukrainian Front, with General Polkovnik Mikhail S. Sharokhin’s 57^th Army positioned to its east with General Major Mikhail B. Anashkin’s LXIV Corps and General Major Dmitri A. Kuprianov’s LXVI Corps, and the front’s other three armies concentrated in the area between Lake Balaton and Budapest. The south-western flank was held by Yugoslav partisan forces.

The communist forces' primary opponent on this sector of the front was General Maximilian de Angelis’s 2^nd Panzerarmee, which included General Rudolf Konrad’s LXVIII Corps and General Hubert Lanz’s XXII Gebirgskorps.

After the 2^nd Ukrainian Front’s successful 'Kechkemét-Budapest Offensive Operation' (29 October/10 December 1944) and 'Szolnok-Budapest Offensive Operation' (29 October/10 December 1944) in the area to the east of Lake Balaton, the German forces to the south-west of the lake retreated, which aided the Bulgarian advance. The Bulgarian 1^st Army breached the first two defensive lines and crossed the Mura river, and then went over to the defensive along the line linking Veliki Kog and Yastrebtzi, remaining there until 7 May. On that day the Bulgarian 1^st Army resumed the offensive, which soon became a matter of the pursuit of fleeing opponents and the capture of German and Hungarian troops.

By 13 May the Bulgarian 1^st Army had reach the Austrian Alps in the Klagenfurt area, and here met the Lieutenant General Sir Richard McCreery’s British 8^th Army moving forward from Italy.