The 9th Panzer Division was a panzer division of the German Army during World War II. It came into existence after 4th Light Division was reorganized in January 1940. The division was headquartered in Vienna, in the German military district Wehrkreis XVII.

Originally raised from Austrian forces annexed into Germany before the war, the 9th Panzer Division was part of most of the German Army's early Blitzkrieg attacks into western Europe. Sweeping east, the division was then a component of Operation Barbarossa, the German attack on the Soviet Union; it was badly mauled at the Battle of Kursk.

Returning to France to rebuild in 1944, the division was rushed to counter Operation Overlord. It was destroyed several successive times by British and American forces as the German Army was pushed back across Europe. The division suffered massive casualties in armor and personnel until it finally collapsed in March 1945. The division's few survivors were pushed into the Ruhr Pocket where they surrendered to the Allies at the end of the war.

In 1942, the division was organized around three regiments. Its tanks were organized into the 33rd Panzer Regiment, which was supported by two regiments of panzergrenadiers, or mechanized infantry. These were the 10th Panzer Grenadier Regiment and the 11th Panzer Grenadier Regiment. Also assigned to the division were the 102nd Panzer Artillery Regiment, the 9th Motorcycle Battalion, the 9th Panzer Reconnaissance Battalion, the 50th Panzer Jager Battalion, the 86th Panzer Pionier Battalion, the 81st Panzer Signal Battalion, the 287th Army Anti-Aircraft Battalion, and the 60th Panzer Divisional Supply Troops.

Following the Anschluss annexation of Austria in 1938, the 4th Light Division was formed in Vienna after converting a mobile division of the Bundesheer (the Austrian Army) in April of that year. It initially consisted of the 33rd Panzer Battalion, the 102nd Motorized Artillery Regiment, and the 10th and 11th Motorized Cavalry Regiments. In 1939, it fought in the Invasion of Poland, on the right flank of Army Group South, attacking out of Slovakia, pushing over the San River on 10 September and capturing Krakowiec on 12 September. It then moved to establish a bridgehead over the Bug River at Krylow on 14 September. The division then turned west, blocking the escape of several units of the Polish Army. In the process the division took tens of thousands of prisoners. On 24 October, the division departed Salzberg, returning to Vienna by train. That winter, it was converted to the 9th Panzer Division and formally redesignated on 3 January 1940. It consisted of the 9th Rifle Brigade, the 33rd Panzer Battalion, the 102nd Panzer Artillery Regiment, and several other divisional units.

Following a further reorganization increasing its strength to two tank battalions and three motorised infantry regiments, the division was sent to the Western Front to participate in the Battle of the Netherlands starting on 10 May 1940. Part of the 18th Army, which defeated The Netherlands in a grueling five days, 9th Panzer Division played an essential role in the German strategy. The division was the only German mechanized force allocated to 18th Army and was intended primarily to link up with airborne forces landed near Rotterdam and The Hague. On 12 May, the division was launched in the south of The Netherlands to exploit a breakthrough by German infantry divisions, quickly advancing to the Moerdijk bridges, which had been captured by Student's paratroopers. Before that, near Breda, the division split up, sending one battalion north over the Moerdijk bridges to try and enter the Dutch National Redoubt, Fortress Holland. On 13 May, however, during its first actual fighting of the campaign, the battalion suffered considerable losses in a failed assault on the centre of Dordrecht.

On 14 May, the battalion stood ready to assault Rotterdam, but the Dutch surrendered the same day after a carpet bombing of that city's civilian centre by the Luftwaffe. The other part of the division went south, after the retreating French 7th Army and the Belgian Army, towards Antwerp and Dunkirk. Parts of 9th Panzer Division, along with SS Leibstandarte, were tasked by Adolf Hitler to conduct an improvised triumphal march through the streets of Amsterdam to underscore the German victory over the Netherlands.

Following the evacuation of Dunkirk, 9th Panzer Division was assigned to Panzer Group Guderian and participated in the Battle of France. During this stage it was under the command of XXXIX Motorized Corps. It pushed through the Weygand Line towards Paris, crossing the Oise River, Aisne River, Marne River and Loire River, taking thousands of prisoners in the process. By the time of the French surrender, the 9th Panzer Division was in Lyon. During the Western campaign, the division was credited with covering more ground than any other German division.