The Porsche 718 is a series of one- or two-seat sports-racing cars built by Porsche from 1957 to 1962. An open-wheel single-seat model was developed for Formula racing.

The 718 was a development of the successful Porsche 550A with improvements made to the body work and suspension. The car's full name is 718 RSK, where "RS" stands for RennSport (sports-racing) and the "K" reflects the shape of the car's revised torsion-bar suspension. It had a mid-engined layout and used the 142 horsepower (106 kW) 1.5-litre Type 547/3 quad-cam engine introduced in the 550A.

In 1957 the Fédération Internationale de l'Automobile (FIA) changed their rules to allow cars with enveloping bodywork to compete in Formula races. That year Porsche entered three 550/1500RS Spyders in the German Grand Prix Formula Two (F2) event. Changes to the cars were minimal, being limited to removing the passenger seats and spare tires.

For 1958 Porsche fielded a modified 718, called the RSK Mittellenker (centre-steer), for F2 events. The bodywork for this car was only slightly different from the sportscar model, but the single seat was now in the centre of the cockpit, with the steering wheel, pedals, and shift lever relocated to accommodate the change and a fairing enclosing more of the cockpit opening. Jean Behra drove the car to a win at the F2 event at Reims that year. At the German Grand Prix at the Nürburgring, driver Edgar Barth placed sixth overall and second in his class. At the Berlin Grand Prix at AVUS the car won both its heat and the F2 class in the hands of driver Masten Gregory.

In 1959 Porsche unveiled the prototype of a narrow, open-wheeled car called the Porsche 718/2 that married the 718's mechanicals with a more traditional single-seat Formula body. The unpainted car was entered in the 1959 Monaco Grand Prix, where driver Wolfgang von Trips qualified twelfth, but crashed on the second lap of the race. At Reims driver Joakim Bonnier finished third. For 1960 the production 718/2, starting with chassis number 718201, received revised bodywork, a 6-speed transaxle, and a wheelbase extended by 100 mm (3.9 in). A total of five cars were built.

In October 1958 the FIA announced another change to the regulations for Formula One (F1). Beginning with the 1961 season, engine capacity would be limited to the same 1.5 litres as Formula Two. This allowed Porsche to use their 718/2s almost unchanged in F1.

For the 1960 season the FIA made changes to the regulation regarding the windscreen and cockpit size. Applying these changes, together with a larger (1.6-litre) Type 547/3 engine developing 160 horsepower (120 kW) and a new double wishbone rear suspension, resulted in the RS 60 model. The RS 60 brought Porsche victory at the 1960 12 Hours of Sebring with a car driven by Hans Herrmann and Olivier Gendebien. 1960 also saw Porsche win the Targa Florio with Hans Herrmann being joined on the winner podium by Jo Bonnier and Graham Hill. The RS 60 also ensured that Porsche successfully defended their European Hill Climb Championship for the third year in a row.

For 1961 the model name was changed to "RS 61" although it was almost identical to the RS 60. An RS 61 won the European Hill Climb Championship.