diff --git a/common/main/wall.h b/common/main/wall.h
index 202fd55d5..bec564e5c 100644
--- a/common/main/wall.h
+++ b/common/main/wall.h
@@ -204,7 +204,7 @@ typedef struct {
 	char    pad;
 } __pack__ wclip;
 
-extern char Wall_names[7][10];
+extern const char Wall_names[7][10];
 
 //#define WALL_IS_DOORWAY(seg,side) wall_is_doorway(seg, side)
 
diff --git a/similar/main/wall.cpp b/similar/main/wall.cpp
index 295b58a9c..32e6a612e 100644
--- a/similar/main/wall.cpp
+++ b/similar/main/wall.cpp
@@ -46,7 +46,7 @@ int Num_cloaking_walls;
 #endif
 
 #ifdef EDITOR
-char	Wall_names[7][10] = {
+const char	Wall_names[7][10] = {
 	"NORMAL   ",
 	"BLASTABLE",
 	"DOOR     ",