diff --git a/default_thai_company/patches.txt b/default_thai_company/patches.txt
index f15c3a9..4c363e9 100644
--- a/default_thai_company/patches.txt
+++ b/default_thai_company/patches.txt
@@ -3,4 +3,5 @@
 # Read docs to understand patches: https://frappeframework.com/docs/v14/user/en/database-migrations
 
 [post_model_sync]
-# Patches added in this section will be executed after doctypes are migrated
\ No newline at end of file
+# Patches added in this section will be executed after doctypes are migrated
+default_thai_company.patches.create_vat_accounts
diff --git a/default_thai_company/patches/__init__.py b/default_thai_company/patches/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/default_thai_company/patches/create_vat_accounts.py b/default_thai_company/patches/create_vat_accounts.py
new file mode 100644
index 0000000..acfc89c
--- /dev/null
+++ b/default_thai_company/patches/create_vat_accounts.py
@@ -0,0 +1,8 @@
+from default_thai_company.tax_withholding import ensure_company_accounts, thai_companies
+
+
+def execute():
+	"""Output VAT / Input VAT were added to COMPANY_ACCOUNTS; Company.on_update
+	only runs on save, so give existing Thai companies the pair."""
+	for company in thai_companies():
+		ensure_company_accounts(company)
diff --git a/default_thai_company/tax_withholding.py b/default_thai_company/tax_withholding.py
index a287e49..83155e8 100644
--- a/default_thai_company/tax_withholding.py
+++ b/default_thai_company/tax_withholding.py
@@ -12,10 +12,23 @@ from frappe.utils import cint, flt
 
 from default_thai_company.utils import money_in_words
 
-# Liability: tax we withhold from suppliers and remit on P.N.D.3/53 (linked on every category).
-# Asset: tax customers withhold from us, creditable against corporate income tax.
+# Tax accounts every Thai company gets (Company.on_update, fixture import, and the
+# create_vat_accounts patch for companies that predate the VAT pair).
+# Withholding: liability = tax we withhold from suppliers, remitted on P.N.D.3/53
+# (linked on every category); asset = tax customers withhold from us, creditable
+# against corporate income tax.
+# VAT: output (ภาษีขาย) collected on sales is payable, input (ภาษีซื้อ) paid on
+# purchases is recoverable; the P.P.30 return nets the two, so they are kept apart.
 LIABILITY_ACCOUNT = "Withholding Tax Payable"
 ASSET_ACCOUNT = "Withholding Tax Receivable"
+OUTPUT_VAT_ACCOUNT = "Output VAT"
+INPUT_VAT_ACCOUNT = "Input VAT"
+COMPANY_ACCOUNTS = (
+	(LIABILITY_ACCOUNT, "Liability"),
+	(ASSET_ACCOUNT, "Asset"),
+	(OUTPUT_VAT_ACCOUNT, "Liability"),
+	(INPUT_VAT_ACCOUNT, "Asset"),
+)
 
 # Preferred parent groups by root type; first match wins, else the root account.
 PARENT_GROUPS = {
@@ -67,9 +80,10 @@ def find_parent_group(company, root_type):
 
 
 def ensure_company_accounts(company):
-	"""Create both withholding accounts for `company`; return the liability account name."""
-	get_or_create_account(company, ASSET_ACCOUNT, "Asset")
-	return get_or_create_account(company, LIABILITY_ACCOUNT, "Liability")
+	"""Create every account in COMPANY_ACCOUNTS for `company`; return the
+	withholding liability account name (the one Tax Withholding Categories link)."""
+	accounts = {name: get_or_create_account(company, name, root_type) for name, root_type in COMPANY_ACCOUNTS}
+	return accounts[LIABILITY_ACCOUNT]
 
 
 def link_company(category, company, account):
@@ -105,7 +119,7 @@ def prepare_fixture_accounts(doc, method=None):
 
 
 def setup_company(doc, method=None):
-	"""Company.on_update: create withholding accounts and link every WHT category."""
+	"""Company.on_update: create the tax accounts and link every WHT category."""
 	if doc.country != "Thailand" or not frappe.db.exists("Account", {"company": doc.name}):
 		return
 
diff --git a/default_thai_company/tests/test_tax_withholding.py b/default_thai_company/tests/test_tax_withholding.py
index f9ad2dc..b7e442e 100644
--- a/default_thai_company/tests/test_tax_withholding.py
+++ b/default_thai_company/tests/test_tax_withholding.py
@@ -8,7 +8,9 @@ from frappe.utils import nowdate
 
 from default_thai_company.tax_withholding import (
 	ASSET_ACCOUNT,
+	INPUT_VAT_ACCOUNT,
 	LIABILITY_ACCOUNT,
+	OUTPUT_VAT_ACCOUNT,
 	get_payment_entry,
 	thai_companies,
 )
@@ -44,16 +46,7 @@ class TestTaxWithholding(FrappeTestCase):
 		).insert()
 		cls.payable = f"{LIABILITY_ACCOUNT} - {ABBR}"
 		cls.receivable = f"{ASSET_ACCOUNT} - {ABBR}"
-
-		cls.vat = frappe.get_doc(
-			{
-				"doctype": "Account",
-				"company": COMPANY,
-				"account_name": "Output VAT",
-				"parent_account": f"Duties and Taxes - {ABBR}",
-				"account_type": "Tax",
-			}
-		).insert()
+		cls.vat = frappe.get_doc("Account", f"{OUTPUT_VAT_ACCOUNT} - {ABBR}")
 
 		frappe.get_doc(
 			{
@@ -137,14 +130,17 @@ class TestTaxWithholding(FrappeTestCase):
 
 	def test_company_creation_adds_accounts_and_links_categories(self):
 		self.assertIn(COMPANY, thai_companies())
-		self.assertEqual(
-			frappe.db.get_value("Account", self.payable, ["root_type", "parent_account"]),
-			("Liability", f"Duties and Taxes - {ABBR}"),
-		)
-		self.assertEqual(
-			frappe.db.get_value("Account", self.receivable, ["root_type", "parent_account"]),
-			("Asset", f"Tax Assets - {ABBR}"),
-		)
+		for account, expected in (
+			(self.payable, ("Liability", f"Duties and Taxes - {ABBR}", "Tax")),
+			(self.receivable, ("Asset", f"Tax Assets - {ABBR}", "Tax")),
+			(f"{OUTPUT_VAT_ACCOUNT} - {ABBR}", ("Liability", f"Duties and Taxes - {ABBR}", "Tax")),
+			(f"{INPUT_VAT_ACCOUNT} - {ABBR}", ("Asset", f"Tax Assets - {ABBR}", "Tax")),
+		):
+			self.assertEqual(
+				frappe.db.get_value("Account", account, ["root_type", "parent_account", "account_type"]),
+				expected,
+				account,
+			)
 
 		categories = frappe.get_all(
 			"Tax Withholding Category", filters={"name": ("like", "WHT %")}, pluck="name"
diff --git a/default_thai_company/translations/th.csv b/default_thai_company/translations/th.csv
index a50b695..9ec2920 100644
--- a/default_thai_company/translations/th.csv
+++ b/default_thai_company/translations/th.csv
@@ -53,3 +53,7 @@ Grand Total,ยอดรวมทั้งสิ้น
 Rounded Total,ยอดรวมปัดเศษ
 Terms and Conditions Details,รายละเอียดข้อตกลงและเงื่อนไข
 Page {0} of {1},หน้า {0} จาก {1}
+Withholding Tax Payable,ภาษีหัก ณ ที่จ่ายค้างจ่าย
+Withholding Tax Receivable,ภาษีถูกหัก ณ ที่จ่าย
+Output VAT,ภาษีขาย
+Input VAT,ภาษีซื้อ