Badge engineering is a term that describes the rebadging of one product (especially cars) as another. Due to the high cost of designing and engineering a totally new model, or establishing a new brand (which may take many years for it to gain acceptance), it is often more cost effective to rebadge a single product multiple times. However, excessive badge engineering can be problematic for car companies, and even detrimental (Plymouth and Eagle are examples). Having a single car sold under multiple identities may hamper overall sales, and can make marketing become difficult. It may also be a problem for a manufacturer to distinguish the differences between two models without damaging the reputation of either.

While differences were originally confined to the badges used on the model, more typically it involves slight styling differences, usually limited to the headlights, tail lights, and front and rear fascias. The term derives from the pot metal trademark emblems fastened onto the outside of the car or onto the dashboard.

Badge engineering is common, but it should not be confused with platform sharing within a company. Platform sharing is different from rebadging, as an automobile platform may be used in many different ways and applications, such as using a single platform to produce and sell a sedan and an SUV. Two such products are legitimately different automobiles, whereas badge engineering involves the sale of essentially a single vehicle.