diff --git a/docs/latex/wx/tex2rtf.ini b/docs/latex/wx/tex2rtf.ini
index 2b5017cf98..a2e9077419 100644
--- a/docs/latex/wx/tex2rtf.ini
+++ b/docs/latex/wx/tex2rtf.ini
@@ -53,6 +53,7 @@ ignoreInput = "ltx.tex"
 \arg [1] {{\it #1}}
 \true [0] {{\tt true}}
 \false [0] {{\tt false}}
+\NULL [0] {{\tt NULL}}
 
 ; make tex2rtf understand \hbox{} macro:
 \hbox [1] {#1}