Teddy Tetzlaff (February 5, 1883 Los Angeles, California – December 8, 1929 Artesia, California) was an Americanracecar driver active in the formative years of auto racing. He competed in the first four Indianapolis 500s, with a highest finish of second in 1912. He earned the nickname "Terrible" Teddy Tetzlaff due to his rough treatment of his vehicles. His wide-open throttle racing style would variously win a race, blow up his engine or cause him to crash. As auto racing strategies evolved from the early "go as fast as you can and see if you can stay on the track," his early dominance of the sport waned.
On March 19, 1911 a Lozier ads claimed, a stock 49 hp (37 kW) model piloted by Teddy Tetzlaff set a world record for 100 mi (160 km) at 1:14:29.
In 1914 the Moross Amusement Company of Ernest Moross engaged Teddy Tetzlaff to campaign the 300 HP Benz, naming it "Blitzen Benz 2." Tetzlaff broke the world land speed record mark by running 142.8 MPH on the Bonneville Salt Flats.
Around 1912 Tetzlaff began appearing as himself in several silent motion pictures produced by comedy pioneer Mack Sennett. He even appeared in one Sennett film The Speed Kings (1913) alongside fellow racing driver Barney Oldfield. He later became an assistant to actor Wallace Reid on Reid's car racing movies. His son Ted Tetzlaff was a noted Hollywood cinematographer.