diff --git a/frappe/custom/doctype/customize_form/customize_form.py b/frappe/custom/doctype/customize_form/customize_form.py
index 8de194fb00..94f25a41aa 100644
--- a/frappe/custom/doctype/customize_form/customize_form.py
+++ b/frappe/custom/doctype/customize_form/customize_form.py
@@ -193,6 +193,16 @@ class CustomizeForm(Document):
 		if prop == "fieldtype":
 			self.validate_fieldtype_change(df, meta_df[0].get(prop), df.get(prop))
 
+		elif prop == "length":
+			old_value_length = cint(meta_df[0].get(prop))
+			new_value_length = cint(df.get(prop))
+
+			if new_value_length and (old_value_length > new_value_length):
+				self.check_length_for_fieldtypes.append({'df': df, 'old_value': meta_df[0].get(prop)})
+				self.validate_fieldtype_length()
+			else:
+				self.flags.update_db = True
+
 		elif prop == "allow_on_submit" and df.get(prop):
 			if not frappe.db.get_value("DocField",
 				{"parent": self.doc_type, "fieldname": df.fieldname}, "allow_on_submit"):
diff --git a/frappe/custom/doctype/customize_form/test_customize_form.py b/frappe/custom/doctype/customize_form/test_customize_form.py
index aef95cd676..266ece8a1e 100644
--- a/frappe/custom/doctype/customize_form/test_customize_form.py
+++ b/frappe/custom/doctype/customize_form/test_customize_form.py
@@ -188,6 +188,26 @@ class TestCustomizeForm(unittest.TestCase):
 	def test_core_doctype_customization(self):
 		self.assertRaises(frappe.ValidationError, self.get_customize_form, 'User')
 
+	def test_save_customization_length_field_property(self):
+		# Using Notification Log doctype as it doesn't have any other custom fields
+		d = self.get_customize_form("Notification Log")
+
+		document_name = d.get("fields", {"fieldname": "document_name"})[0]
+		document_name.length = 255
+		d.run_method("save_customization")
+
+		self.assertEqual(frappe.db.get_value("Property Setter",
+			{"doc_type": "Notification Log", "property": "length", "field_name": "document_name"}, "value"), '255')
+
+		self.assertTrue(d.flags.update_db)
+
+		length = frappe.db.sql("""SELECT character_maximum_length
+			FROM information_schema.columns
+			WHERE table_name = 'tabNotification Log'
+			AND column_name = 'document_name'""")[0][0]
+
+		self.assertEqual(length, 255)
+
 	def test_custom_link(self):
 		try:
 			# create a dummy doctype linked to Event