The Waffen-SS were frontline combat troops trained to fight in Germany's battles during World War II. During the early campaigns against Czechoslovakia and Poland, military SS units were of regiment size and drawn from existing armed SS formations:
- Leibstandarte, Hitler's personal bodyguard
- Death's-Head Battalions (German: Totenkopfverbände), which administered the concentration camps
- Dispositional Troops, (German: Verfügungstruppe)
For the invasion of France and the Low Countries in 1940 (Fall Gelb) the three SS-VT and three of the SS-TV regiments were each organized into divisions (the future 2nd "Das Reich" and 3rd "Totenkopf"), and another division was raised from the Ordnungspolizei (later the 4th "Polizei"). Following the campaign, these units together with the Leibstandarte and additional SS-TV Standarten were amalgamated into the newly-formed Kommandoamt der Waffen-SS within the SS Führungshauptamt.
In 1941 Himmler announced that additional Waffen-SS Freiwilligen units would be raised from non-German foreign nationals. His goal was to acquire additional manpower from occupied nations or prisoners of war. These foreign legions eventually included volunteers from Belgium, Britain and its Dominions, Denmark, Finland, France, Norway, Sweden, and the Netherlands.
While the Waffen-SS remained officially outside the armed forces (Wehrmacht) and under Himmler's authority, they were placed under the operational command of the Armed Forces High Command (OKW) or Army High Command (OKH), and were largely funded by the Wehrmacht. During the war, the Waffen-SS grew to 38 divisions. The most famous are the 1st SS Division Leibstandarte SS Adolf Hitler (LSSAH), 2nd SS Panzer Division Das Reich, 3rd SS Division Totenkopf, 5th SS Panzer Division Wiking, and the 12th SS Panzer Division Hitlerjugend.
The Waffen-SS maintained several "Foreign Legions" of personnel from conquered territories and countries allied to Germany. The majority wore a distinctive national collar patch and preceded their SS rank titles with the prefix Waffen instead of SS. Volunteers from Scandinavian countries filled the ranks of two divisions, the 5th "Wiking" and 11th "Nordland." Belgian Flemings joined Dutchmen to form the "Nederland" Legion, their Walloon compatriots joined the Sturmbrigade "Wallonien". There was also a French volunteer division, 33rd Waffen Grenadier Division of the SS Charlemagne (1st French).
Racial restrictions were relaxed to the extent that Ukrainian Slavs, Albanians from Kosovo, Arabs, Turkic Tatars, and even Asians from Dutch East Indies (Indonesia)units were recruited. The Ukrainians and the Tatars had both suffered persecution under Joseph Stalin and their motive was a hatred of communism rather than sympathy for National Socialism. The exiled Grand Mufti of Jerusalem, Hajj Amin al-Husayni, used hatred of Serbs and Jews to recruit an entire Waffen-SS division of Bosnian Muslims, the 13th SS Division "Handschar" (Scimitar). The year-long Soviet occupation and oppression of the Baltic states at the beginning of World War II produced volunteers for Latvian and Estonian Waffen-SS units. The Estonian Legion, for example, had 1,280 volunteers under training by the end of 1942. However, by 1 February 1944 the German military situation on the Eastern front had worsened. As the result, another 10,000 Estonia men were conscripted into the Waffen-SS. Approximately 25,000 men served in the Estonian SS division (with thousands more conscripted into the "Police Front" battalions and border guard units). After 1943 most men from the east were conscripts. However, some other occupied countries such as Greece, Lithuania, Czechoslovakia, and Poland never formed formal Waffen-SS legions. With that said, there were some countrymen that were in the service of the Waffen-SS. In Greece, the fascist organisation ESPO tried to create a Greek SS division, but the attempt was abandoned when its leader was assassinated.
The Indische Freiwilligen Infanterie Regiment 950 (also known at various stages as the Indische Freiwilligen-Legion der Waffen-SS, the Legion Freies Indien, and Azad Hind Fauj) was created in August 1942, chiefly from disaffected Indian soldiers of the British Indian Army, captured by the Axis in North Africa. Many, if not most, of the Indian volunteers who switched sides to fight with the German Army and against the British were strongly nationalistic supporters of the exiled, anti-British, former president of the Indian National Congress, Netaji (the Leader) Subhas Chandra Bose. See also the Tiger Legion and the Indian National Army.