Reliant Motor Company was a British car manufacturer based in Tamworth, Staffordshire, England. It was founded in 1935 and ended car production in 2002, the company had been known as "Reliant Motor Company" (or RMC for short) until the 1990s when it became "Reliant Motors" and then finally became "Reliant Cars LTD" after production had ended of the Robin as the company was restructured to be a car import business. It is now a dormant company and the only entity left is a separate parts company created called "Reliant Partsworld" which produces parts for Reliant vehicles.

Reliant was a large manufacturing company that mainly produced vehicles for niche markets, such as small three-wheeled vehicles and sports cars. It was best known for the three-wheeled Reliant Robin, but produced a variety of vehicles over 60 years, including sports cars, convertibles and commercial vehicles. Approximately half a million Reliant vehicles were produced and sold in at least nine countries. For a period from the 1970s until the 1990s, Reliant was the UK's second biggest British-owned car manufacturer behind British Leyland.

To make their vehicles light, the company decided to produce car bodies from fibreglass in the mid-1950s. From this, Reliant became a pioneer in fibreglass design, techniques, and developments. Reliant also produced kitchen worktops, train bodies, and personal watercraft shells from fibreglass. In the 1970s, Reliant was the largest producer of fibreglass in Europe.

Reliant became the second-largest British-owned car company in the 1970s after the forming of British Leyland, Reliant had five factories and sold vehicles to seven countries.