The 4 Hours of Red Bull Ring (originally known as the 500 km Zeltweg) was an endurance sports car event held near Spielberg, Austria.

Originally based at the Zeltweg Airfield, the race moved to the Österreichring and was lengthened to a 1000 km distance and there it continued to be a regular event in the World Sportscar Championship until 1976.

However, with rule changes in the evolved World Championship of Makes in 1976, the event became limited to a maximum of six hours due to the decrease in overall speed of the competitors.

Following the rebuilding of the Österreichring into the new A1-Ring in 1997, the FIA GT Championship briefly resurrected the sportscar endurance race in a modified form.

The FIA chose not to return to the circuit after the 2001 event, and the A1-Ring was eventually partially torn down in 2004, until it was rebuilt as Red Bull Ring in 2011.