In the automotive industry, rebadging (also known as badge engineering, an intentionally ironic misnomer in that little or no actual engineering takes place) is a form of market segmentation used by automobile manufacturers around the world. To allow for product differentiation without designing or engineering a new model or brand (at high cost or risk), a manufacturer creates a distinct automobile by applying a new "badge" or trademark (brand, logo, or manufacturer's name/make/marque) to an existing product line.

The term originated with the practice of replacing an automobile's emblems to create an ostensibly new model sold by a different maker. Changes may be confined to swapping badges and emblems, or may encompass minor styling differences, as with cosmetic changes to headlights, taillights, front and rear fascias, and even outer body skins. More extreme examples involve differing engines and drivetrains. The objective is "to spread the huge development costs of a new vehicle over as many cars as possible". An example is General Motors' rebadging of the Camaro as the Firebird, a successful model from the 1960s through to the 2000s. In most cases, consumers are interested in each brand's focus "on the unique elements of styling and driving characteristics". Some cars would not be marketed without the cost savings that are obtained from this practice, and carmakers can develop many "different models – all wearing different badges – off the one platform".

In several countries including Japan, manufacturers often use the phrase "OEM supply" or "OEM-supplied" to denote vehicles that are a rebadged model from or for other manufacturers.

Although platform sharing can often involve rebadging and rebranding, it can extend further, as the design may be used across multiple configurations. For example, a single platform may underpin a sedan, hatchback, or SUV/CUV body designs.

Automotive industry rebadging can be compared with white-label products in other consumer goods industries, such as consumer electronics and power tools.

The first known case of badge engineering appeared in 1917 with the Texan automobile assembled in Fort Worth, Texas, that made use of Elcar bodies made in Elkhart, Indiana.

"Probably the industry's first example of one car becoming another" occurred in 1926 when Nash Motors' newly introduced smaller-sized Ajax models were discontinued in 1926 after over 22,000 Ajax cars were sold during the brand's inaugural year. The chairman and CEO of the company, Charles W. Nash, ordered that the Ajax models be marketed as the "Nash Light Six", Nash being a known and respected automobile brand. Production was stopped for two days so Nash emblems, hubcaps, and radiator shells could be exchanged on all unshipped Ajax cars. Conversion kits were also distributed at no charge to Ajax owners to transform their cars and protect the investment they had made in purchasing an automobile made by Nash.

Starting with the beginning of General Motors in 1909, chassis and platforms were shared with all brands. GMC, which historically was a truck builder, began to offer its products branded as Chevrolet, and vehicles produced by GM were built on common platforms shared with Chevrolet, Oakland, Oldsmobile, Buick, and Cadillac. Exterior appearances were gradually upgraded between these vehicle brands. This was partly because all bodywork was provided by Fisher Body which was bought by GM in 1925, and the introduction of the Art and Color Section in 1928, directed by Harley Earl. For the 1958 model year, GM was promoting its fiftieth year of production and introduced anniversary models for each brand; Cadillac, Buick, Oldsmobile, Pontiac, and Chevrolet. The 1958 models shared an almost identical appearance on all models for each brand and made special luxury models with a shared appearance; Cadillac Eldorado Seville, Buick Limited Riviera, Oldsmobile Starfire 98, Pontiac Bonneville Catalina, and the Chevrolet Bel-Air Impala.