diff --git a/pegjs/postgresql.pegjs b/pegjs/postgresql.pegjs
index e90d6cea..91234548 100644
--- a/pegjs/postgresql.pegjs
+++ b/pegjs/postgresql.pegjs
@@ -5639,8 +5639,28 @@ assign_stmt_list
     return createList(head, tail);
   }
 
+assign_stmt_timezone
+  = KW_TIME __ 'ZONE'i __ e:interval_expr __ KW_TO __ r:interval_unit {
+    // => { type: 'assign';  left: expr_list; symbol: 'to'; right: interval_unit; }
+    return {
+      type: 'assign',
+      left: { type: 'expr_list', value: [{ type: 'origin', value: 'time zone' }, e], separator: ' ' },
+      symbol: 'to',
+      right: { type: 'origin', value: r }
+    };
+  }
+  / KW_TIME __ 'ZONE'i __ s:KW_TO? __ e:(literal_numeric / literal_string / KW_LOCAL / 'default'i) {
+    // => { type: 'assign'; left: literal_string; symbol?: 'to'; right: literal; }
+    return {
+      type: 'assign',
+      left: { type: 'origin', value: 'time zone' },
+      symbol: s ? 'to' : null,
+      right: typeof e === 'string' ? { type: 'origin', value: e } : e
+    };
+  }
 assign_stmt
-  = va:(var_decl / without_prefix_var_decl) __ s:(KW_ASSIGN / KW_ASSIGIN_EQUAL / KW_TO) __ e:proc_expr {
+  = assign_stmt_timezone
+  / va:(var_decl / without_prefix_var_decl) __ s:(KW_ASSIGN / KW_ASSIGIN_EQUAL / KW_TO) __ e:proc_expr {
     // => { type: 'assign'; left: var_decl | without_prefix_var_decl; symbol: ':=' | '='; right: proc_expr; }
     return {
       type: 'assign',
diff --git a/src/assign.js b/src/assign.js
index c78c9b02..4678ebca 100644
--- a/src/assign.js
+++ b/src/assign.js
@@ -1,5 +1,5 @@
 import { exprToSQL } from './expr'
-import { hasVal } from './util'
+import { hasVal, toUpper } from './util'
 
 function assignToSQL(expr) {
   /** @type {Object} */
@@ -7,7 +7,7 @@ function assignToSQL(expr) {
   left.keyword = keyword
   const leftVar = exprToSQL(left)
   const rightVal = exprToSQL(right)
-  return [leftVar, symbol, rightVal].filter(hasVal).join(' ')
+  return [leftVar, toUpper(symbol), rightVal].filter(hasVal).join(' ')
 }
 
 export {
diff --git a/test/postgres.spec.js b/test/postgres.spec.js
index ce0252b1..8d7710b2 100644
--- a/test/postgres.spec.js
+++ b/test/postgres.spec.js
@@ -1698,6 +1698,20 @@ describe('Postgres', () => {
 
   neatlyNestTestedSQL(SQL_LIST)
 
+  describe('set time zone', () => {
+    it('should support set time zone', () => {
+      let sql = "SET TIME ZONE INTERVAL '00:00' HOUR TO MINUTE;"
+      expect(getParsedSql(sql, opt)).to.equal(sql.slice(0, -1))
+      sql = "SET TIME ZONE 'America/Los_Angeles';"
+      expect(getParsedSql(sql, opt)).to.equal(sql.slice(0, -1))
+      sql = 'SET TIME ZONE -8;'
+      expect(getParsedSql(sql, opt)).to.equal(sql.slice(0, -1))
+      sql = 'SET TIME ZONE LOCAL;'
+      expect(getParsedSql(sql, opt)).to.equal(sql.slice(0, -1))
+      sql = 'SET TIME ZONE DEFAULT;'
+      expect(getParsedSql(sql, opt)).to.equal(sql.slice(0, -1))
+    })
+  })
   describe('tables to sql', () => {
     it('should parse object tables', () => {
       const ast = parser.astify(SQL_LIST[100].sql[0], opt)