The Sultan is famous for his vast automobile collection. In 1998, the British car magazine Autocar published undercover photographs of the Sultan's cars, which included unique modifications of Ferraris and Bentleys. It has been said that he has at least 3,000 to 6,000 cars and has bought over U.S.$4 billion worth of high-performance cars.

The number purchased by his business interests and the number actually used by himself and his family differ greatly. According to Guinness World Records the Sultan's personal private collection has 500 Rolls-Royces — the largest collection of that marque in the world. During the 1990s, his family accounted for almost half of all Rolls-Royce purchases, bulk buying slightly modified vehicles for diplomats and adding unique cars to their own collection. He also owns the very last Rolls-Royce Phantom VI, a 1992 state landaulette.

Among his collection are the Porsche Carrera GT, Lamborghini Diablo Jota, Porsche 959, Bugatti EB110, Bugatti Veyron (regular and Pur Sang edition), Lamborghini Murcielago LP640, Maybach 62, Jaguar XJR-15 and six Dauer 962s. He is also the owner of six models of the Ferrari FX, the original red show model of the Bentley Continental R, two fully operational versions of the Ferrari Mythos concept car, both of the Ferrari 456 GT Sedans, the only right hand drive Mercedes-Benz CLK-GTR in the world, five McLaren F1s including both black LM models and three Cizeta-Moroder V16T cars. He also possesses a Formula One car as driven by every Formula 1 World Drivers Champion since the 1980 Formula One season, particularly the ones driven in the last race for each season. A prime example of this is Jacques Villeneuve's Williams FW19 which still bears the collision damage courtesy of Michael Schumacher in the 1997 European Grand Prix.

He has a special interest in buying one-of-a-kind concept cars, including the Bentley Java and Bentley Dominator 4x4, whilst leaving slightly more common race cars such as the Aston Martin AM3 or the modified Mercedes-Benz 300SL to his brother Jefri. The collection of vehicles was for the most part stored and serviced in five aircraft hangars, where specialist teams from the various manufacturers would maintain the collection.

The Daily Mirror (UK) reported on 26 October 2007 that the Sultan owned 232 Mercedes-Benzes, 224 Ferraris, 245 Bentleys, 150 BMWs, 165 Jaguars, 125 Porsches, 130 Rolls-Royces, and 20 Lamborghinis.