The BMW 303 was a small family saloon produced by BMW in 1933 and 1934. It was the first BMW motor car with a six-cylinder engine and the first BMW motor car with the "kidney grille" associated with the brand. The platform developed for the 303 was used for several other BMW cars, including the BMW 309, a four-cylinder version of the 303, the BMW 315, a 1.5 litre version of the 303 which replaced it in 1934 and was built until 1937, the BMW 319, a 1.9 litre version of the 303 produced alongside the 315 from 1935 to 1937, and the BMW 329, a development of the 319 with styling based on the newer, larger BMW 326, that briefly replaced the 319 in 1937.

The 303 was the first BMW car to use a straight-6 engine. The M78 1182 cc six-cylinder engine was developed from the four-cylinder engine used in the 3/20. The engine had the same bore and stroke as the four, but the bore spacing was increased to allow for further increases in bore and to provide for crankshaft bearings between the ends of the crankshaft.

At the time it was being made, the 303 was the least expensive six-cylinder car in Germany. However, it was considered underpowered, with a top speed of 56 miles per hour (90 km/h). The combination of soft spring rates at the front and hard spring rates at the rear caused understeer, body roll, and a generally unsettling pitching movement. 2300 BMW 303s were produced up to 1934, when the 303 was replaced by the 315.