The TSS Duke of Rothesay was a railway steamer passenger ship that operated in Europe from 1956 to 1975.

Along with her sister ships the TSS Duke of Lancaster and the TSS Duke of Argyll she was amongst the last passenger-only steamers built for British Railways (at that time, also a ferry operator).

[1] She was a replacement for the 1928 steamer built by the London Midland & Scottish Railway, RMS Duke of Rothesay.

Built at William Denny & Brothers, Dumbarton and completed in 1956, she was designed to operate as both a passenger ferry (primarily on the Heysham-Belfast route) and as a cruise ship.

In March 1967, she was converted to a side loading car ferry by Cammell Laird to be used on the Fishguard to Rosslare service, which continued until the Caledonian Princess took over in 1971.