Kapfenberg ([ˈkapfənbɛʁk]), with 22,182 inhabitants in 2023, is the third largest city in Styria, Austria, and lies in the valley of the Mürz near the town of Bruck an der Mur. The town's landmark is Burg Oberkapfenberg. Every year in June, the Ritterfest ("knights' festival") takes place at the castle, which is one of the largest events of its kind in Austria.

Kapfenbergs main employer is the steel manufacturer voestalpine. The town has a swimming complex, a football stadium (Franz Fekete Stadium) used by the club Kapfenberger SV, and an ice rink. The Kapfenberg Bulls is a team in the Österreichische Basketball Bundesliga, the highest professional basketball league in Austria.

In 1970, Kapfenberg hosted the European Team Chess Championship, which was won by the Soviet Union.

Kapfenberg is located around 43 kilometres north of the Styrian capital Graz and around 117 kilometres southwest of the Austrian capital Vienna.

The town lies between the Mürztaler Alps and Fischbach Alps. The highest point is the Floning at 1583 metres above sea level, the lowest point at 483 metres above sea level is the Mürz on the municipal border with Bruck an der Mur, which flows into the Mur around 1.2 kilometres downstream.

• Wulfing von Stubenberg, (DE Wiki) (1259–1318), Catholic bishop
• Ruth Feldgrill-Zankel (born 1942), politician (ÖVP)
• Ernst Kovacic, (DE Wiki) (born 1943), violinist and conductor
• Manfred Wegscheider, (DE Wiki) (born 1949), politician (SPÖ)
• Peter Nehr (born 1952), US-American politician
• Peter Pilz (born 1954), politician (The Greens)
• Brigitte Schwarz, (DE Wiki) (born 1960), politician (SPÖ). Mayor of Kapfenberg 2005–2012
• Melitta Breznik (born 1961), doctor and writer
• Ulrike Diebold (born 1961), an Austrian physicist and materials scientist

Media related to Kapfenberg at Wikimedia Commons

• (in German) Official website