From 1965 through 1969, Porsche's 912 eased the transition between the 356 and the 911.  Conceived as a European model, the Porsche factory announced the 912 in early April 1965.  With the great aerodynamics, ergonomics, style, and quality of construction as a six-cylinder 911, the 912 had other advantages as well.  Fans of the 356 appreciated the similarities to that model; for example a proven 356-based flat four-cylinder fuel-efficient motor delivering 64 SAE horsepower/ liter from behind the rear axle .  With the flat-four, an early 912 weighs about 250 pounds less than a standard 911 of the same year, resulting in improved front-rear weight distribution.  And the combination of fuel-efficiency, low-weight, and low-drag translated the 912 into a "green" low-fuel consumption vehicle capable of up to 30 MPG highway, decades before hybrid cars.

First available to European customers by June 1965, the 912 soon became a market leader, particularly in the USA.  The 912 outsold the 911 almost two to one in 1966.  Constructed in late 1966, the 100,000th Porsche built was a 912 Targa® police car.  The 912 won Car and Driver's 1967 "Readers Choice" Poll for its class.  With its nimble handling combined with high reliability, a racing 912 won the European Rally Championship for its class in 1967.

In 1969 the late great race car driver Mark Donohue road tested the 911 and 912 for Car and Driver and said:

"And you've got to admire them [Porsche] for getting so much out of a relatively small engine, even the 912 - although I was most impressed with the handling.  The cars have remarkable suspension systems."

Overall production gradually shifted from the fuel-efficient 912 to the higher-horsepower six-cylinder 911.  During the 1968 production year, about 6300 912s were constructed versus about 8000 911 cars.  912s continued in production in 1969 until the introduction of the mid-engine, Targa style 914 and 914-6 in late 1969.  Ironically, after production of the 914 ceased in late 1975, the fuel-injected 912E model appeared in 1976, powered by a 2.0 liter 914-derived engine.  When 912E production ended, Porsche had constructed 34,959 of the Type 912/912E model.