The Austin Princess III DS5 was introduced in 1953 to replace the Princess II DS3. Mechanically identical to the Princess I & II it was powered by Austin's 'D' series 3995cc six-cylinder engine mated to a column change 4-speed manual gearbox.

An automatic gearbox became optional from late 1955. Externally the car differed from the earlier cars by having a new 'Vanden Plas' designed radiator grille. New front doors and wings, as used on the DM4 Limousine, were fitted. The wing line continuation on the front doors was lifted and made more horizontal. Rounded and bolder front and rear bumpers were fitted and initially the front sidelights were fitted atop the front wings, rather than the oblong sidelights fitted below the headlights on the Princess II. 

Once again Vanden Plas changed the design of the seats with leather being the standard covering but West of England Cloth remaining an option. The sunroof and radio now became an extra-cost option.

Some 299 saloons (DS5) and 51 Touring Limousines with glass division (DM5) were produced before manufacture ceased in 1956.