These orthographic guidelines of the National Commission for Stratigraphy Belgium (NCS) serve as a writing guide for Belgian stratigraphic unit names in English, Dutch, French and German. It is concluded with a rationale on how the ICS rules are transposed, and how the Belgian-Dutch translation of the international chronostratigraphic chart is made. These guidelines are compiled by Kris Welkenhuysen on 31/03/2025 with input from the NCS members. Special thanks to Juliane Scheder for helping with the German translation.