diff --git a/fuzz/fuzz_seeds/postgres_alter_extension.sql b/fuzz/fuzz_seeds/postgres_alter_extension.sql
index 44eb414408..f82cba6b10 100644
--- a/fuzz/fuzz_seeds/postgres_alter_extension.sql
+++ b/fuzz/fuzz_seeds/postgres_alter_extension.sql
@@ -19,3 +19,4 @@ ALTER EXTENSION citext ADD TEXT SEARCH DICTIONARY public.dict;
 ALTER EXTENSION citext DROP TEXT SEARCH PARSER public.pgrm;
 ALTER EXTENSION citext ADD TEXT SEARCH TEMPLATE public.tpl;
 ALTER EXTENSION citext DROP DATABASE db_name;
+ALTER EXTENSION citext ADD EXTENSION other_ext;
diff --git a/src/ast/ddl.rs b/src/ast/ddl.rs
index d46b877d91..e0247f7b34 100644
--- a/src/ast/ddl.rs
+++ b/src/ast/ddl.rs
@@ -4940,6 +4940,8 @@ pub enum AlterExtensionMember {
     Database(Ident),
     /// `EVENT TRIGGER object_name`
     EventTrigger(Ident),
+    /// `EXTENSION object_name`
+    Extension(Ident),
     /// `FOREIGN DATA WRAPPER object_name`
     ForeignDataWrapper(Ident),
     /// `FOREIGN TABLE object_name`
@@ -5000,6 +5002,7 @@ impl fmt::Display for AlterExtensionMember {
             AlterExtensionMember::Conversion(name) => write!(f, "CONVERSION {name}"),
             AlterExtensionMember::Database(name) => write!(f, "DATABASE {name}"),
             AlterExtensionMember::EventTrigger(name) => write!(f, "EVENT TRIGGER {name}"),
+            AlterExtensionMember::Extension(name) => write!(f, "EXTENSION {name}"),
             AlterExtensionMember::ForeignDataWrapper(name) => {
                 write!(f, "FOREIGN DATA WRAPPER {name}")
             }
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 75f077873a..9230c03ec3 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -12553,6 +12553,8 @@ impl<'a> Parser<'a> {
             Ok(AlterExtensionMember::Database(self.parse_identifier()?))
         } else if self.parse_keywords(&[Keyword::EVENT, Keyword::TRIGGER]) {
             Ok(AlterExtensionMember::EventTrigger(self.parse_identifier()?))
+        } else if self.parse_keyword(Keyword::EXTENSION) {
+            Ok(AlterExtensionMember::Extension(self.parse_identifier()?))
         } else if self.parse_keywords(&[Keyword::FOREIGN, Keyword::DATA, Keyword::WRAPPER]) {
             Ok(AlterExtensionMember::ForeignDataWrapper(
                 self.parse_identifier()?,
diff --git a/tests/sqlparser_postgres.rs b/tests/sqlparser_postgres.rs
index 4ac59bd631..0626ae2093 100644
--- a/tests/sqlparser_postgres.rs
+++ b/tests/sqlparser_postgres.rs
@@ -13534,6 +13534,7 @@ fn alter_extension_member_round_trip_forms(action: &str) {
         format!("ALTER EXTENSION ext_name {action} CONVERSION conv"),
         format!("ALTER EXTENSION ext_name {action} DATABASE db_name"),
         format!("ALTER EXTENSION ext_name {action} EVENT TRIGGER trg"),
+        format!("ALTER EXTENSION ext_name {action} EXTENSION other_ext"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN DATA WRAPPER fdw"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN TABLE ft"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN TABLE schema.ft"),
@@ -13730,6 +13731,7 @@ fn parse_alter_extension_add_member() {
         "CONVERSION",
         "DATABASE",
         "EVENT TRIGGER",
+        "EXTENSION",
         "FOREIGN DATA WRAPPER",
         "FOREIGN TABLE",
         "LANGUAGE",