diff --git a/app/main/forms.py b/app/main/forms.py
index 7856b1bc5..31ff09737 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -327,5 +327,5 @@ class ServiceSmsSender(Form):
 
     def validate_sms_sender(form, field):
         import re
-        if not re.match('^[a-zA-Z0-9\s]+$', field.data):
+        if field.data and not re.match('^[a-zA-Z0-9\s]+$', field.data):
             raise ValidationError('Sms text message sender can only contain alpha-numeric characters')
diff --git a/tests/app/main/test_validators.py b/tests/app/main/test_validators.py
index 535936eab..f8b1a6490 100644
--- a/tests/app/main/test_validators.py
+++ b/tests/app/main/test_validators.py
@@ -131,6 +131,10 @@ def test_sms_sender_form_validation(app_, mock_get_user_by_email):
         form.validate()
         assert not form.errors
 
+        form.sms_sender.data = ''
+        form.validate()
+        assert not form.errors
+
         form.sms_sender.data = 'morethanelevenchars'
         form.validate()
         assert "Text message sender can't be longer than 11 characters" == form.errors['sms_sender'][0]