diff --git a/app/main/forms.py b/app/main/forms.py
index 90dd618be..b8af1c9dc 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -45,7 +45,7 @@ from app.main.validators import (
     CommonlyUsedPassword,
     CsvFileValidator,
     DoesNotStartWithDoubleZero,
-    LettersNumbersFullStopsAndUnderscoresOnly,
+    LettersNumbersSingleQuotesFullStopsAndUnderscoresOnly,
     MustContainAlphanumericCharacters,
     NoCommasInPlaceHolders,
     NoEmbeddedImagesInSVG,
@@ -1734,7 +1734,7 @@ class ServiceSmsSenderForm(StripWhitespaceForm):
             DataRequired(message="Cannot be empty"),
             Length(max=11, message="Enter 11 characters or fewer"),
             Length(min=3, message="Enter 3 characters or more"),
-            LettersNumbersFullStopsAndUnderscoresOnly(),
+            LettersNumbersSingleQuotesFullStopsAndUnderscoresOnly(),
             DoesNotStartWithDoubleZero(),
         ]
     )
diff --git a/app/main/validators.py b/app/main/validators.py
index 9d09fbe0c..d3b267332 100644
--- a/app/main/validators.py
+++ b/app/main/validators.py
@@ -144,9 +144,9 @@ class BroadcastLength:
             )
 
 
-class LettersNumbersFullStopsAndUnderscoresOnly:
+class LettersNumbersSingleQuotesFullStopsAndUnderscoresOnly:
 
-    regex = re.compile(r'^[a-zA-Z0-9\s\._]+$')
+    regex = re.compile(r"^[a-zA-Z0-9\s\._']+$")
 
     def __init__(self, message='Use letters and numbers only'):
         self.message = message
diff --git a/tests/app/main/test_validators.py b/tests/app/main/test_validators.py
index 5798dd2d4..9458dbd62 100644
--- a/tests/app/main/test_validators.py
+++ b/tests/app/main/test_validators.py
@@ -187,46 +187,35 @@ def test_if_string_contains_alphanumeric_characters_does_not_raise(string):
     MustContainAlphanumericCharacters()(None, _gen_mock_field(string))
 
 
+@pytest.mark.parametrize(
+    "sms_sender,error_expected,error_message",
+    [
+        ('', True, 'Cannot be empty'),
+        ('22', True, 'Enter 3 characters or more'),
+        ('333', False, None),
+        ('elevenchars', False, None),  # 11 chars
+        ('twelvecharas', True, 'Enter 11 characters or fewer'),  # 12 chars
+        ('###', True, 'Use letters and numbers only'),
+        ('00111222333', True, 'Cannot start with 00'),
+        ('UK_GOV', False, None),  # Underscores are allowed
+        ('UK.GOV', False, None),  # Full stops are allowed
+        ("'UC'", False, None),  # Straight single quotes are allowed
+    ]
+)
 def test_sms_sender_form_validation(
     client,
     mock_get_user_by_email,
+    sms_sender,
+    error_expected,
+    error_message
 ):
     form = ServiceSmsSenderForm()
+    form.sms_sender.data = sms_sender
 
-    form.sms_sender.data = 'elevenchars'
     form.validate()
-    assert not form.errors
 
-    form.sms_sender.data = ''
-    form.validate()
-    assert "Cannot be empty" == form.errors['sms_sender'][0]
-
-    form.sms_sender.data = 'morethanelevenchars'
-    form.validate()
-    assert "Enter 11 characters or fewer" == form.errors['sms_sender'][0]
-
-    form.sms_sender.data = '###########'
-    form.validate()
-    assert 'Use letters and numbers only' == form.errors['sms_sender'][0]
-
-    # Underscores are allowed
-    form.sms_sender.data = 'UK_GOV'
-    form.validate()
-    assert not form.errors
-
-    # Full stops are allowed
-    form.sms_sender.data = 'UK.GOV'
-    form.validate()
-    assert not form.errors
-
-    form.sms_sender.data = '22'
-    form.validate()
-    assert 'Enter 3 characters or more' == form.errors['sms_sender'][0]
-
-    form.sms_sender.data = '333'
-    form.validate()
-    assert not form.errors
-
-    form.sms_sender.data = '00111222333'
-    form.validate()
-    assert "Cannot start with 00" == form.errors['sms_sender'][0]
+    if error_expected:
+        assert form.errors
+        assert error_message == form.errors['sms_sender'][0]
+    else:
+        assert not form.errors