diff --git a/src/zscript/zcc-parse.lemon b/src/zscript/zcc-parse.lemon
index da940dc6f2..b180381c47 100644
--- a/src/zscript/zcc-parse.lemon
+++ b/src/zscript/zcc-parse.lemon
@@ -104,6 +104,7 @@ translation_unit(X) ::= error.											{ X = NULL; }
 external_declaration(X) ::= class_definition(A).						{ X = A; }
 external_declaration(X) ::= struct_def(A).								{ X = A; }
 external_declaration(X) ::= enum_def(A).								{ X = A; }
+external_declaration(X) ::= const_def(A).								{ X = A; }
 
 /* Optional bits. */
 opt_semicolon ::= .