diff --git a/ast/ast.go b/ast/ast.go
index 445eb898..295b21b4 100644
--- a/ast/ast.go
+++ b/ast/ast.go
@@ -58,6 +58,7 @@ func (CreateView) isStatement()         {}
 func (CreateIndex) isStatement()        {}
 func (CreateRole) isStatement()         {}
 func (AlterTable) isStatement()         {}
+func (AlterIndex) isStatement()         {}
 func (DropTable) isStatement()          {}
 func (DropIndex) isStatement()          {}
 func (DropRole) isStatement()           {}
@@ -225,6 +226,7 @@ func (CreateSequence) isDDL()     {}
 func (AlterTable) isDDL()         {}
 func (DropTable) isDDL()          {}
 func (CreateIndex) isDDL()        {}
+func (AlterIndex) isDDL()         {}
 func (DropIndex) isDDL()          {}
 func (CreateRole) isDDL()         {}
 func (DropRole) isDDL()           {}
@@ -292,6 +294,15 @@ func (ScalarSchemaType) isSchemaType() {}
 func (SizedSchemaType) isSchemaType()  {}
 func (ArraySchemaType) isSchemaType()  {}
 
+// IndexAlternation represents ALTER INDEX action.
+type IndexAlternation interface {
+	Node
+	isIndexAlternation()
+}
+
+func (AddStoredColumn) isIndexAlternation()  {}
+func (DropStoredColumn) isIndexAlternation() {}
+
 // DML represents data manipulation language in SQL.
 //
 // https://cloud.google.com/spanner/docs/data-definition-language
@@ -1626,6 +1637,19 @@ type AlterTable struct {
 	TableAlternation TableAlternation
 }
 
+// AlterIndex is ALTER INDEX statement node.
+//
+//	ALTER INDEX {{.Name | sql}} {{.IndexAlternation | sql}}
+type AlterIndex struct {
+	// pos = Alter
+	// end = IndexAlternation.end
+
+	Alter token.Pos // position of "ALTER" keyword
+
+	Name             *Ident
+	IndexAlternation IndexAlternation
+}
+
 // AlterChangeStream is ALTER CHANGE STREAM statement node.
 //
 //	ALTER CHANGE STREAM {{.Name | sql}} {{.ChangeStreamAlternation | sql}}
@@ -1939,6 +1963,30 @@ type InterleaveIn struct {
 	TableName *Ident
 }
 
+// AddStoredColumn is ADD STORED COLUMN clause in ALTER INDEX.
+//
+//	ADD STORED COLUMN {{.Name | sql}}
+type AddStoredColumn struct {
+	// pos = Add
+	// end = Name.end
+
+	Add token.Pos // position of "ADD" keyword
+
+	Name *Ident
+}
+
+// DropStoredColumn is DROP STORED COLUMN clause in ALTER INDEX.
+//
+//	DROP STORED COLUMN {{.Name | sql}}
+type DropStoredColumn struct {
+	// pos = Drop
+	// end = Name.end
+
+	Drop token.Pos // position of "DROP" keyword
+
+	Name *Ident
+}
+
 // DropIndex is DROP INDEX statement node.
 //
 //	DROP INDEX {{if .IfExists}}IF EXISTS{{end}} {{.Name | sql}}
diff --git a/ast/ast_test.go b/ast/ast_test.go
index 8b70fbb2..c9c1f999 100644
--- a/ast/ast_test.go
+++ b/ast/ast_test.go
@@ -13,6 +13,7 @@ func TestStatement(t *testing.T) {
 	Statement(&CreateSequence{}).isStatement()
 	Statement(&CreateRole{}).isStatement()
 	Statement(&AlterTable{}).isStatement()
+	Statement(&AlterIndex{}).isStatement()
 	Statement(&DropTable{}).isStatement()
 	Statement(&DropIndex{}).isStatement()
 	Statement(&DropRole{}).isStatement()
@@ -128,6 +129,7 @@ func TestDDL(t *testing.T) {
 	DDL(&AlterTable{}).isDDL()
 	DDL(&DropTable{}).isDDL()
 	DDL(&CreateIndex{}).isDDL()
+	DDL(&AlterIndex{}).isDDL()
 	DDL(&DropIndex{}).isDDL()
 	DDL(&CreateRole{}).isDDL()
 	DDL(&DropRole{}).isDDL()
@@ -170,6 +172,11 @@ func TestSchemaType(t *testing.T) {
 	SchemaType(&ArraySchemaType{}).isSchemaType()
 }
 
+func TestIndexAlternation(t *testing.T) {
+	IndexAlternation(&AddStoredColumn{}).isIndexAlternation()
+	IndexAlternation(&DropStoredColumn{}).isIndexAlternation()
+}
+
 func TestDML(t *testing.T) {
 	DML(&Insert{}).isDML()
 	DML(&Delete{}).isDML()
diff --git a/ast/pos.go b/ast/pos.go
index c0d14c89..a6aaa402 100644
--- a/ast/pos.go
+++ b/ast/pos.go
@@ -692,6 +692,15 @@ func (s *Storing) End() token.Pos { return s.Rparen + 1 }
 func (i *InterleaveIn) Pos() token.Pos { return i.Comma }
 func (i *InterleaveIn) End() token.Pos { return i.TableName.End() }
 
+func (a *AlterIndex) Pos() token.Pos { return a.Alter }
+func (a *AlterIndex) End() token.Pos { return a.IndexAlternation.End() }
+
+func (a *AddStoredColumn) Pos() token.Pos { return a.Add }
+func (a *AddStoredColumn) End() token.Pos { return a.Name.End() }
+
+func (a *DropStoredColumn) Pos() token.Pos { return a.Drop }
+func (a *DropStoredColumn) End() token.Pos { return a.Name.End() }
+
 func (d *DropIndex) Pos() token.Pos { return d.Drop }
 func (d *DropIndex) End() token.Pos { return d.Name.End() }
 
diff --git a/ast/sql.go b/ast/sql.go
index 02b7df27..c31d71bc 100644
--- a/ast/sql.go
+++ b/ast/sql.go
@@ -1057,6 +1057,18 @@ func (i *InterleaveIn) SQL() string {
 	return ", INTERLEAVE IN " + i.TableName.SQL()
 }
 
+func (a *AlterIndex) SQL() string {
+	return "ALTER INDEX " + a.Name.SQL() + " " + a.IndexAlternation.SQL()
+}
+
+func (a *AddStoredColumn) SQL() string {
+	return "ADD STORED COLUMN " + a.Name.SQL()
+}
+
+func (a *DropStoredColumn) SQL() string {
+	return "DROP STORED COLUMN " + a.Name.SQL()
+}
+
 func (d *DropIndex) SQL() string {
 	sql := "DROP INDEX "
 	if d.IfExists {
diff --git a/parser.go b/parser.go
index 42757cce..7648d90c 100644
--- a/parser.go
+++ b/parser.go
@@ -1997,6 +1997,8 @@ func (p *Parser) parseDDL() ast.DDL {
 		switch {
 		case p.Token.IsKeywordLike("TABLE"):
 			return p.parseAlterTable(pos)
+		case p.Token.IsKeywordLike("INDEX"):
+			return p.parseAlterIndex(pos)
 		case p.Token.IsKeywordLike("CHANGE"):
 			return p.parseAlterChangeStream(pos)
 		}
@@ -2851,6 +2853,53 @@ func (p *Parser) parseAlterColumn() ast.TableAlternation {
 	}
 }
 
+func (p *Parser) parseAlterIndex(pos token.Pos) *ast.AlterIndex {
+	p.expectKeywordLike("INDEX")
+
+	name := p.parseIdent()
+
+	var alternation ast.IndexAlternation
+	switch {
+	case p.Token.IsKeywordLike("ADD"):
+		alternation = p.parseAddStoredColumn()
+	case p.Token.IsKeywordLike("DROP"):
+		alternation = p.parseDropStoredColumn()
+	default:
+		p.panicfAtToken(&p.Token, "expected pseudo keyword: ADD, DROP, but: %s", p.Token.AsString)
+	}
+
+	return &ast.AlterIndex{
+		Alter:            pos,
+		Name:             name,
+		IndexAlternation: alternation,
+	}
+}
+
+func (p *Parser) parseAddStoredColumn() ast.IndexAlternation {
+	pos := p.expectKeywordLike("ADD").Pos
+	p.expectKeywordLike("STORED")
+	p.expectKeywordLike("COLUMN")
+
+	name := p.parseIdent()
+
+	return &ast.AddStoredColumn{
+		Add:  pos,
+		Name: name,
+	}
+}
+
+func (p *Parser) parseDropStoredColumn() ast.IndexAlternation {
+	pos := p.expectKeywordLike("DROP").Pos
+	p.expectKeywordLike("STORED")
+	p.expectKeywordLike("COLUMN")
+
+	name := p.parseIdent()
+
+	return &ast.DropStoredColumn{
+		Drop: pos,
+		Name: name,
+	}
+}
 func (p *Parser) parseDropTable(pos token.Pos) *ast.DropTable {
 	p.expectKeywordLike("TABLE")
 	ifExists := p.parseIfExists()
diff --git a/testdata/input/ddl/alter_index_add_stored_column.sql b/testdata/input/ddl/alter_index_add_stored_column.sql
new file mode 100644
index 00000000..0e8bdc3e
--- /dev/null
+++ b/testdata/input/ddl/alter_index_add_stored_column.sql
@@ -0,0 +1 @@
+alter index foo add stored column bar
diff --git a/testdata/input/ddl/alter_index_drop_stored_column.sql b/testdata/input/ddl/alter_index_drop_stored_column.sql
new file mode 100644
index 00000000..306aae0f
--- /dev/null
+++ b/testdata/input/ddl/alter_index_drop_stored_column.sql
@@ -0,0 +1 @@
+alter index foo drop stored column bar
diff --git a/testdata/result/ddl/alter_index_add_stored_column.sql.txt b/testdata/result/ddl/alter_index_add_stored_column.sql.txt
new file mode 100644
index 00000000..558262b9
--- /dev/null
+++ b/testdata/result/ddl/alter_index_add_stored_column.sql.txt
@@ -0,0 +1,23 @@
+--- alter_index_add_stored_column.sql
+alter index foo add stored column bar
+
+--- AST
+&ast.AlterIndex{
+  Alter: 0,
+  Name:  &ast.Ident{
+    NamePos: 12,
+    NameEnd: 15,
+    Name:    "foo",
+  },
+  IndexAlternation: &ast.AddStoredColumn{
+    Add:  16,
+    Name: &ast.Ident{
+      NamePos: 34,
+      NameEnd: 37,
+      Name:    "bar",
+    },
+  },
+}
+
+--- SQL
+ALTER INDEX foo ADD STORED COLUMN bar
diff --git a/testdata/result/ddl/alter_index_drop_stored_column.sql.txt b/testdata/result/ddl/alter_index_drop_stored_column.sql.txt
new file mode 100644
index 00000000..cbad680e
--- /dev/null
+++ b/testdata/result/ddl/alter_index_drop_stored_column.sql.txt
@@ -0,0 +1,23 @@
+--- alter_index_drop_stored_column.sql
+alter index foo drop stored column bar
+
+--- AST
+&ast.AlterIndex{
+  Alter: 0,
+  Name:  &ast.Ident{
+    NamePos: 12,
+    NameEnd: 15,
+    Name:    "foo",
+  },
+  IndexAlternation: &ast.DropStoredColumn{
+    Drop: 16,
+    Name: &ast.Ident{
+      NamePos: 35,
+      NameEnd: 38,
+      Name:    "bar",
+    },
+  },
+}
+
+--- SQL
+ALTER INDEX foo DROP STORED COLUMN bar
diff --git a/testdata/result/statement/alter_index_add_stored_column.sql.txt b/testdata/result/statement/alter_index_add_stored_column.sql.txt
new file mode 100644
index 00000000..558262b9
--- /dev/null
+++ b/testdata/result/statement/alter_index_add_stored_column.sql.txt
@@ -0,0 +1,23 @@
+--- alter_index_add_stored_column.sql
+alter index foo add stored column bar
+
+--- AST
+&ast.AlterIndex{
+  Alter: 0,
+  Name:  &ast.Ident{
+    NamePos: 12,
+    NameEnd: 15,
+    Name:    "foo",
+  },
+  IndexAlternation: &ast.AddStoredColumn{
+    Add:  16,
+    Name: &ast.Ident{
+      NamePos: 34,
+      NameEnd: 37,
+      Name:    "bar",
+    },
+  },
+}
+
+--- SQL
+ALTER INDEX foo ADD STORED COLUMN bar
diff --git a/testdata/result/statement/alter_index_drop_stored_column.sql.txt b/testdata/result/statement/alter_index_drop_stored_column.sql.txt
new file mode 100644
index 00000000..cbad680e
--- /dev/null
+++ b/testdata/result/statement/alter_index_drop_stored_column.sql.txt
@@ -0,0 +1,23 @@
+--- alter_index_drop_stored_column.sql
+alter index foo drop stored column bar
+
+--- AST
+&ast.AlterIndex{
+  Alter: 0,
+  Name:  &ast.Ident{
+    NamePos: 12,
+    NameEnd: 15,
+    Name:    "foo",
+  },
+  IndexAlternation: &ast.DropStoredColumn{
+    Drop: 16,
+    Name: &ast.Ident{
+      NamePos: 35,
+      NameEnd: 38,
+      Name:    "bar",
+    },
+  },
+}
+
+--- SQL
+ALTER INDEX foo DROP STORED COLUMN bar