The Palace comprises two apartments, one each for the king and queen. Each has a hall, presence chamber, and bedchamber, with various small rooms known as closets. The Renaissance decoration continued inside, although little has survived the building's military use, excepting the carved stone fireplaces.
The ceiling of the King's Presence Chamber was originally decorated with a series of carved oak portrait roundels known as the Stirling Heads, described as "among the finest examples of Scottish Renaissance wood-carving now extant." The carvings were taken down following a ceiling collapse in 1777, and of an estimated 56 original heads, 38 survive.
Most were given to the Smith Institute in Stirling, and these are now preserved in the castle, and three more are in the National Museum of Scotland, Edinburgh. Another two are on display in the Thieves Pot, a preserved 16th-century jail within the Thistles Shopping Centre. Some of the portraits are believed to be of kings, queens, or courtiers, and others are thought to show classical or Biblical figures.
As with the exterior carving, similarities to German sources have been noted, and in particular to a ceiling in Wawel, Poland. A £12 million project to recreate the grandeur of the Royal Palace, re-opened to the public during the weekend of the 5th and 6 June 2011. The work which has taken a decade of research and craftsmanship, restored six royal apartments, to how they would have looked in the 1540s, when this was the childhood home of Mary Queen of Scots as well as the ongoing restoration of the seven hand-woven tapestries; four of which have been completed with the last one due to be finished in 2013