Lochranza Castle is a tower house in Lochranza, on the northern part of the Isle of Arran. It was built in the late 13th century by Dougall MacSween, Lord of Knapdale, but most of today's structure was built in the 16th century.

Throughout its history, Lochranza Castle was associated with several notable figures. In 1262, King Alexander III granted the castle to Walter Stewart, Earl of Menteith. It is believed that Robert the Bruce landed at Lochranza in 1306 during his campaign to claim the Scottish throne. By 1371, the castle was owned by Robert II and used as a royal hunting lodge. In the 1490s, James IV utilized it during his campaign against the Lord of the Isles. ​By the late 18th century, the castle fell into disuse and became the ruin seen today.