diff --git a/aegisub/src/command/command.cpp b/aegisub/src/command/command.cpp
index c69c67230..6dbc8b05e 100644
--- a/aegisub/src/command/command.cpp
+++ b/aegisub/src/command/command.cpp
@@ -63,7 +63,7 @@ namespace cmd {
 			cmd(c);
 	}
 
-	wxBitmap const& Command::Icon(int size) {
+	wxBitmap const& Command::Icon(int size) const {
 		return icon::get(name(), size);
 	}
 
diff --git a/aegisub/src/command/command.h b/aegisub/src/command/command.h
index 008fe805a..d3966b240 100644
--- a/aegisub/src/command/command.h
+++ b/aegisub/src/command/command.h
@@ -105,7 +105,7 @@ namespace cmd {
 
 		/// Request icon.
 		/// @param size Icon size.
-		wxBitmap const& Icon(int size);
+		wxBitmap const& Icon(int size) const;
 
 		/// Command function
 		virtual void operator()(agi::Context *c)=0;