The Subaru Rex (other names: Ace, Viki or Sherpa) is a Japanese passenger car belonging to the kei-car class, which debuted on the market in 1972 and its series production continued until 1992. In the chronologically earliest version, produced in 1972-1976, the car was 299.5 cm long, 129.5 cm wide, with an wheelbase of 192 cm. The car's curb weight was only 480 kilograms.

The Rex model was introduced to the market to replace the concern's offer Subaru Corporation the R-2 model, which went into production in 1969. Compared to its predecessor, the new car differed primarily in design, but also used a wider range of engines. Initially, the manufacturer planned to sell it primarily on the domestic Japanese market, but over time the vehicle began to be exported to Western Europe, South America and Africa. In total, three generations of Subaru Rex were created. Chronologically, the first one was produced in the years 1972-1981 and was powered by 2-cylinder engines with a capacity of 356 cm3 to 544 cm3. It was offered mainly in the hatchback version. In the period 1981-1986, the second generation was produced, which significantly differed from the previous design, as well as engines with a capacity of 544 cm3 and 665 cm3 were used. Finally, the third generation, which made its debut in 1986, received a much wider range of engines from 544cc to 758cc. It also received a new exterior design and improved its reliability. Ultimately, the Rex was replaced by the Vivio in the Subaru lineup.