diff --git a/docs/grammar/README.md b/docs/grammar/README.md
index 04616cec3a..dc162c438e 100644
--- a/docs/grammar/README.md
+++ b/docs/grammar/README.md
@@ -328,7 +328,7 @@ and therefore we have rules like
 
 
 ```
-unary-expression = primary-expression
+unary-expression = postfix-expression
                  / "!" unary-expression
                  / "-" unary-expression
 ```
diff --git a/docs/grammar/abnf-grammar.txt b/docs/grammar/abnf-grammar.txt
index fc903b6c85..c9902eca19 100644
--- a/docs/grammar/abnf-grammar.txt
+++ b/docs/grammar/abnf-grammar.txt
@@ -263,7 +263,7 @@
 ; the relative precedence and the associativity of expression operators,
 ; and therefore we have rules like
 ;
-;  unary-expression = primary-expression
+;  unary-expression = postfix-expression
 ;                   / "!" unary-expression
 ;                   / "-" unary-expression
 ;