Colours were ubiquitous in the medieval world, and castles were no exception. While in the eyes of most people their rich colour schemes manifested power and wealth, some could also read the more nuanced messages these colours conveyed. The main objective of this paper is to discuss the use and role of colour in the interiors of castles of medieval Bohemia and Poland. The picture is complemented by the analysis of colour decorations of defensive residences of the Teutonic Order, for which colour schemes of external facades can be addressed as well. The dis-cussion takes into account the varying state of preservation and draws from the available writ-ten accounts. To present the most complete picture possible, we discuss royal residences, for which unfortunately limited data is available, as well as better-preserved castles of dukes and knights. We discuss the identified iconographic programmes and their chivalric, heraldic, and hagiographic motifs. Also within the scope of our discussion are late forms of floral decorations, known as “green chambers”. The numerous examples presented in the paper prove that colour was an important tool of visual social communication in castle architecture: it complemented the symbolism, and sometimes carried an independent message.