SS Sir Walter Scott is a small steamship that has provided pleasure cruises and a ferry service on Loch Katrine in the scenic Trossachs of Scotland for more than a century, and is the only surviving screw steamer in regular passenger service in Scotland. She is named after the writer Walter Scott, who set his 1810 poem Lady of the Lake, and his 1818 novel Rob Roy around Loch Katrine.

Loch Katrine is a freshwater loch in the Trossachs area of the Scottish Highlands, east of Loch Lomond, within the historic county and registration county of Perthshire and the contemporary district of Stirling. The loch is about 8 miles (13 km) long and 1 mile (1.6 km) wide at its widest point, and runs the length of Strath Gartney. It is within the drainage basins of the River Teith and River Forth.