diff --git a/fuzz/fuzz_seeds/postgres_alter_extension.sql b/fuzz/fuzz_seeds/postgres_alter_extension.sql
index dc1fee895c..c63e6ef6f9 100644
--- a/fuzz/fuzz_seeds/postgres_alter_extension.sql
+++ b/fuzz/fuzz_seeds/postgres_alter_extension.sql
@@ -8,3 +8,4 @@ ALTER EXTENSION citext DROP FOREIGN TABLE public.ft;
 ALTER EXTENSION citext ADD SEQUENCE public.seq;
 ALTER EXTENSION citext DROP SCHEMA other;
 ALTER EXTENSION citext DROP PROCEDURAL LANGUAGE plpgsql;
+ALTER EXTENSION citext ADD ACCESS METHOD btree;
diff --git a/src/ast/ddl.rs b/src/ast/ddl.rs
index b0fcc014ee..8a9bb98337 100644
--- a/src/ast/ddl.rs
+++ b/src/ast/ddl.rs
@@ -4926,6 +4926,8 @@ pub enum AlterExtensionOperation {
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
 pub enum AlterExtensionMember {
+    /// `ACCESS METHOD object_name`
+    AccessMethod(Ident),
     /// `FOREIGN TABLE object_name`
     ForeignTable(ObjectName),
     /// `[ PROCEDURAL ] LANGUAGE object_name`
@@ -4969,6 +4971,7 @@ impl fmt::Display for AlterExtensionOperation {
 impl fmt::Display for AlterExtensionMember {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
+            AlterExtensionMember::AccessMethod(name) => write!(f, "ACCESS METHOD {name}"),
             AlterExtensionMember::ForeignTable(name) => write!(f, "FOREIGN TABLE {name}"),
             AlterExtensionMember::Language { procedural, name } => {
                 if *procedural {
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index f0ca9648f7..52458899c1 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -12539,7 +12539,9 @@ impl<'a> Parser<'a> {
 
     /// Parse a member object of `ALTER EXTENSION ADD` or `ALTER EXTENSION DROP`
     fn parse_alter_extension_member(&mut self) -> Result<AlterExtensionMember, ParserError> {
-        if self.parse_keywords(&[Keyword::FOREIGN, Keyword::TABLE]) {
+        if self.parse_keywords(&[Keyword::ACCESS, Keyword::METHOD]) {
+            Ok(AlterExtensionMember::AccessMethod(self.parse_identifier()?))
+        } else if self.parse_keywords(&[Keyword::FOREIGN, Keyword::TABLE]) {
             Ok(AlterExtensionMember::ForeignTable(
                 self.parse_object_name(false)?,
             ))
diff --git a/tests/sqlparser_postgres.rs b/tests/sqlparser_postgres.rs
index f8326403bd..47768e4543 100644
--- a/tests/sqlparser_postgres.rs
+++ b/tests/sqlparser_postgres.rs
@@ -13528,6 +13528,7 @@ fn parse_case_ending_in_end_keyword_is_not_silently_dropped() {
 
 fn alter_extension_member_round_trip_forms(action: &str) {
     let sqls = [
+        format!("ALTER EXTENSION ext_name {action} ACCESS METHOD btree"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN TABLE ft"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN TABLE schema.ft"),
         format!("ALTER EXTENSION ext_name {action} LANGUAGE plpgsql"),
@@ -13665,6 +13666,19 @@ fn parse_alter_extension_set_schema() {
 fn parse_alter_extension_add_member() {
     alter_extension_member_round_trip_forms("ADD");
 
+    match pg_and_generic().verified_stmt("ALTER EXTENSION ext_name ADD ACCESS METHOD btree") {
+        Statement::AlterExtension(AlterExtension { name, operation }) => {
+            assert_eq!(name, Ident::new("ext_name"));
+            assert_eq!(
+                operation,
+                AlterExtensionOperation::Add(AlterExtensionMember::AccessMethod(Ident::new(
+                    "btree"
+                )))
+            );
+        }
+        other => panic!("unexpected statement: {other:?}"),
+    }
+
     match pg_and_generic().verified_stmt("ALTER EXTENSION ext_name ADD PROCEDURAL LANGUAGE plpgsql")
     {
         Statement::AlterExtension(AlterExtension {
@@ -13700,6 +13714,7 @@ fn parse_alter_extension_add_member() {
     }
 
     for member in [
+        "ACCESS METHOD",
         "FOREIGN TABLE",
         "LANGUAGE",
         "MATERIALIZED VIEW",