The Alfa Romeo Tipo 312, 312 or 12C-312 was a 3-litre formula racing car that was used in the 1938 Grand Prix season; drivers were Raymond Sommer, Giuseppe Farina, Eugenio Siena, Clemente Biondetti, Carlo Pintacuda, Jean-Pierre Wimille, Gianfranco Comotti, Piero Taruffi and Pietro Ghersi.

Tipo 312 was one of three Alfa Romeo cars designed for the new rules in 1938, which differed mainly by the engine; the other two cars were the Alfa Romeo Tipo 308 with straight-8 engine and Alfa Romeo Tipo 316 with a V16 engine.

The car was based on unsuccessful Alfa Romeo 12C-37; it was made easier to control than its predecessor.

The engine in 312 is 3-litre 60° V-12 with roots supercharger, 2 valves/cyl, 2,995 cc (182.8 cu in) capacity 66 mm × 73 mm (2.60 in × 2.87 in) produced 320 bhp (239 kW) at 6500 rpm; it was more powerful than 308 but it was still not really competitive with German rivals.