The Fiat 126 (Type 126) is a four-passenger, rear-engine, city car manufactured and marketed by Fiat over a twenty-eight year production run from 1972 until 2000, over a single generation. Introduced by Fiat in October 1972 at the Turin Auto Show, the 126 replaced the Fiat 500, using major elements from its design. A subsequent iteration, marketed as the 126 Bis, used a horizontally oriented, water-cooled engine and featured a rear hatchback.

The majority of 126s (some 3.3 million) were manufactured in Tychy and Bielsko-Biała plants, Poland and were marketed as the Polski Fiat 126p in many markets. Fiat stopped marketing the 126 in 1993 in favor of its new front-engined Cinquecento. Total production reached approximately 4.7 million units.

In Poland, the car became a people's car, and a cultural icon, earning the nickname Maluch, meaning "The Little One" or "Toddler", a name that eventually became official in 1997, when 'Maluch' started appearing, badged on the rear of the car.

In early 2020, the 28-year production run of the Fiat 126 was counted as the twenty-sixth most long-lived single generation car in history by Autocar magazine.