The Museum's Collection of Wall-Paintings, though not very large, is invaluable, as it gives an outline of the development of monumental religious painting on Greek soil in the Byzantine and Post-Byzantine period.
   
It was necessary to detach the wall-paintings which are now in the Museum for a variety of important reasons – e.g. the discovery of earlier painted layers, demolition of churches and so on – and in most cases this was done in the 1960s by the staff of what was then the Central Conservation Laboratory (KES). 
   
The earliest wall-paintings in the collection, recently acquired by the Museum, come from a large and splendid built complex, most probably public buildings, situated on Herod Atticus Street in Athens
   
But the most important group of wall-paintings come from the church of the Dormition of the Virgin on the banks of the River Megdova, nears Episkopi in Evrytania.  This church is now at the bottom of the artificial lake which was created in the 1960s during the construction of the Acheloos Dam.  In the process of removing the wall-paintings in order to preserve them a further two paint layers were found under the top layer, which dates to the thirteenth century: one from the eleventh century and an earlier one from the ninth.
   
Many of the wall-paintings in the collection come from small, thirteenth-century churches, scattered all over Greece, while fragments and larger sections of paintings have been detached from Saint Photida in Veroki (fifteenth century), the Palaiopanagia church in Lakonia (14th century) and Prophet Elijah in Staropazaro, near Athens (fifteenth century). 
   
A unique group of wall-paintings, recently securely dated to 1449-1450, comes from the Virgin Hodegitria in Apolpena in Lefkas.  Its importance lies in the fact that it combines Palaiologan features with Late Gothic painting in incomparable fashion and reflects the multicultural environment in Lefkas in the fifteenth century.
   
The collection also contains Post-Byzantine wall-paintings from the church of Saint Andrew, the katholikon of the Monastery of Saint Philothei in Attica (seventeenth century), the church of the Virgin in Merenda, also in Attica, and the church of the Virgin in Delphi (eighteenth century).