Heinz-Harald Frentzen (German pronunciation: [haɪ̯nt͡s ˈha.ʁalt ˈfʁeːn.t͡sn̩]; born 18 May 1967) is a German former racing driver, who competed in Formula One from 1994 to 2003. Frentzen was runner-up in the Formula One World Drivers' Championship in 1997 with Williams, and won three Grands Prix across 10 seasons.

Born in Mönchengladbach, Frentzen began his racing career aged 12 in karting, winning several titles including the junior direct-drive German Kart Championship. He progressed to junior formulae in 1985, winning several races in Formula Ford before finishing runner-up in the 1989 German Formula Three Championship amidst a title battle with Karl Wendlinger and Michael Schumacher. After three seasons of racing in Japan, Frentzen signed with Sauber in 1994, making his Formula One debut at the Brazilian Grand Prix. He remained at Sauber—now under Red Bull sponsorship—the following season, achieving his maiden podium at the Italian Grand Prix. After scoring several point finishes in his 1996 campaign, Frentzen joined Williams to replace reigning World Champion Damon Hill alongside Jacques Villeneuve. Frentzen achieved his maiden victory at the San Marino Grand Prix, taking several podiums as he finished runner-up to Villeneuve after Schumacher's collision with him at the last race of the season saw his disqualification from the standings. Williams suffered their first winless season since 1988 with the FW20, prompting his departure to Jordan in a swap with Ralf Schumacher. Frentzen achieved further wins at the French and Italian Grands Prix in 1999, finishing third in the World Drivers' Championship to Mika Häkkinen and Eddie Irvine. After struggling for form in 2000, Frentzen was dropped by Jordan after the 2001 British Grand Prix, swapping with Jean Alesi to join Prost. After Prost went bankrupt at the end of the 2001 season, Frentzen spent two seasons with Arrows and Sauber before retiring at the conclusion of 2003, having achieved three wins, two pole positions, six fastest laps and 18 podiums in Formula One.

Outside of Formula One, Frentzen competed full-time in the Deutsche Tourenwagen Masters from 2004 to 2006, as well as competing in the all-star Speedcar Series in both of its seasons. Frentzen entered two editions of the 24 Hours of Le Mans in 1992 and 2008, finishing fourth in class at the latter with Aston Martin.