diff --git a/app/dao/organisation_dao.py b/app/dao/organisation_dao.py
index 80708f266..6082ae376 100644
--- a/app/dao/organisation_dao.py
+++ b/app/dao/organisation_dao.py
@@ -1,6 +1,6 @@
 from app import db
 from app.dao.dao_utils import transactional
-from app.models import Organisation
+from app.models import Organisation, Service
 
 
 def dao_get_organisations():
@@ -9,10 +9,20 @@ def dao_get_organisations():
     ).all()
 
 
+def dao_get_organisation_services(organisation_id):
+    return Organisation.query.filter_by(
+        id=organisation_id
+    ).one().services
+
+
 def dao_get_organisation_by_id(organisation_id):
     return Organisation.query.filter_by(id=organisation_id).one()
 
 
+def dao_get_organisation_by_service_id(service_id):
+    return Organisation.query.join(Organisation.services).filter(Service.id == service_id).first()
+
+
 @transactional
 def dao_create_organisation(organisation):
     db.session.add(organisation)
@@ -23,3 +33,12 @@ def dao_update_organisation(organisation_id, **kwargs):
     return Organisation.query.filter_by(id=organisation_id).update(
         kwargs
     )
+
+
+@transactional
+def dao_add_service_to_organisation(service, organisation_id):
+    organisation = Organisation.query.filter_by(
+        id=organisation_id
+    ).one()
+
+    organisation.services.append(service)
diff --git a/tests/app/conftest.py b/tests/app/conftest.py
index bf675ed2b..5da494062 100644
--- a/tests/app/conftest.py
+++ b/tests/app/conftest.py
@@ -17,6 +17,7 @@ from app.models import (
     TemplateHistory,
     ApiKey,
     Job,
+    Organisation,
     Notification,
     NotificationHistory,
     InvitedUser,
@@ -40,6 +41,7 @@ from app.models import (
     ServiceEmailReplyTo
 )
 from app.dao.users_dao import (create_user_code, create_secret_code)
+from app.dao.organisation_dao import dao_create_organisation
 from app.dao.services_dao import (dao_create_service, dao_add_user_to_service)
 from app.dao.templates_dao import dao_create_template
 from app.dao.api_key_dao import save_model_api_key
@@ -1044,6 +1046,13 @@ def sample_inbound_numbers(notify_db, notify_db_session, sample_service):
     return inbound_numbers
 
 
+@pytest.fixture
+def sample_organisation(notify_db, notify_db_session):
+    org = Organisation(name='sample organisation')
+    dao_create_organisation(org)
+    return org
+
+
 @pytest.fixture
 def restore_provider_details(notify_db, notify_db_session):
     """
diff --git a/tests/app/dao/test_organisation_dao.py b/tests/app/dao/test_organisation_dao.py
index a72670cb8..610d71ed5 100644
--- a/tests/app/dao/test_organisation_dao.py
+++ b/tests/app/dao/test_organisation_dao.py
@@ -1,11 +1,17 @@
+import pytest
+from sqlalchemy.exc import IntegrityError
+
 from app.dao.organisation_dao import (
     dao_get_organisations,
     dao_get_organisation_by_id,
+    dao_get_organisation_by_service_id,
+    dao_get_organisation_services,
     dao_update_organisation,
+    dao_add_service_to_organisation,
 )
 from app.models import Organisation
 
-from tests.app.db import create_organisation
+from tests.app.db import create_organisation, create_service
 
 
 def test_get_organisations_gets_all_organisations_alphabetically_with_active_organisations_first(
@@ -40,14 +46,60 @@ def test_update_organisation(notify_db, notify_db_session):
     updated_name = 'new name'
     create_organisation()
 
-    organisation = Organisation.query.all()
+    organisation = Organisation.query.one()
 
-    assert len(organisation) == 1
-    assert organisation[0].name != updated_name
+    assert organisation.name != updated_name
 
-    dao_update_organisation(organisation[0].id, **{'name': updated_name})
+    dao_update_organisation(organisation.id, **{'name': updated_name})
 
-    organisation = Organisation.query.all()
+    organisation = Organisation.query.one()
 
-    assert len(organisation) == 1
-    assert organisation[0].name == updated_name
+    assert organisation.name == updated_name
+
+
+def test_add_service_to_organisation(notify_db, notify_db_session, sample_service, sample_organisation):
+    dao_add_service_to_organisation(sample_service, sample_organisation.id)
+
+    assert len(sample_organisation.services) == 1
+
+
+def test_add_service_to_multiple_organisation_raises_error(
+        notify_db, notify_db_session, sample_service, sample_organisation):
+    another_org = create_organisation()
+    dao_add_service_to_organisation(sample_service, sample_organisation.id)
+
+    with pytest.raises(IntegrityError):
+        dao_add_service_to_organisation(sample_service, another_org.id)
+
+    assert len(sample_organisation.services) == 1
+    assert sample_organisation.services[0] == sample_service
+
+
+def test_get_organisation_services(notify_db, notify_db_session, sample_service, sample_organisation):
+    another_service = create_service(service_name='service 2')
+    another_org = create_organisation()
+
+    dao_add_service_to_organisation(sample_service, sample_organisation.id)
+    dao_add_service_to_organisation(another_service, sample_organisation.id)
+
+    org_services = dao_get_organisation_services(sample_organisation.id)
+    other_org_services = dao_get_organisation_services(another_org.id)
+
+    assert len(org_services) == 2
+    assert org_services[0].name == sample_service.name
+    assert org_services[1].name == another_service.name
+    assert not other_org_services
+
+
+def test_get_organisation_by_service_id(notify_db, notify_db_session, sample_service, sample_organisation):
+    another_service = create_service(service_name='service 2')
+    another_org = create_organisation()
+
+    dao_add_service_to_organisation(sample_service, sample_organisation.id)
+    dao_add_service_to_organisation(another_service, another_org.id)
+
+    organisation_1 = dao_get_organisation_by_service_id(str(sample_service.id))
+    organisation_2 = dao_get_organisation_by_service_id(str(another_service.id))
+
+    assert organisation_1 == sample_organisation
+    assert organisation_2 == another_org