Currently, the “authenticity of architectural heritage” is one of the basic concepts of restoration theory and practice. The article presents modern interpretations of “authenticity” in the humanities, each of which reveals a certain aspect of the concept. It is shown that the idea of “authenticity” changes over time, differs in various cultural traditions and is determined by the world view of a particular historical era. Two approaches to the interpretation of the “authenticity of architectural heritage” are distinguished as follows: the historical approach, the basis of which is the understanding of the architectural monument as documentary evidence of the past and the connection of the times, and the structural approach, which rejects continuity and allows the possibility of “replacing” parts of the whole.