diff --git a/xos/core/models/service.py b/xos/core/models/service.py
index 979a295..0692baf 100644
--- a/xos/core/models/service.py
+++ b/xos/core/models/service.py
@@ -18,4 +18,42 @@
     value = StrippedCharField(help_text="Attribute Value", max_length=1024)
     service = models.ForeignKey(Service, related_name='serviceattributes', help_text="The Service this attribute is associated with")
 
+class Tenant(PlCoreBase):
+    """ A tenant is a relationship between two entities, a subscriber and a
+        provider.
+
+        The subscriber can be a User, a Service, or a Tenant.
+
+        The provider is always a Service.
+    """
+    kind = StrippedCharField(max_length=30)
+    provider_service = models.ForeignKey(Service, related_name='tenants')
+    subscriber_service = models.ForeignKey(Service, related_name='subscriptions', blank=True, null=True)
+    subscriber_tenant = models.ForeignKey("Tenant", related_name='subscriptions', blank=True, null=True)
+    subscriber_user = models.ForeignKey("User", related_name='subscriptions', blank=True, null=True)
+    service_specific_id = StrippedCharField(max_length=30)
+    service_specific_attribute = models.TextField()
+
+    def __unicode__(self):
+        if self.subscriber_service:
+            return u'%s tenant %s on %s' % (str(self.kind), str(self.subscriber_service), str(self.provider_service))
+        else:
+            return u'%s tenant %s on %s' % (str(self.kind), str(self.subscriber_tenant), str(self.provider_service))
+
+    # helper for extracting things from a json-encoded service_specific_attribute
+    def get_attribute(self, name, default=None):
+        if self.service_specific_attribute:
+            attributes = json.loads(self.service_specific_attribute)
+        else:
+            attributes = {}
+        return attributes.get(name, default)
+
+    def set_attribute(self, name, value):
+        if self.service_specific_attributes:
+            attributes = json.loads(self.service_specific_attribute)
+        else:
+            attributes = {}
+        attributes[name]=value
+        self.service_specific_attribute = json.dumps(attributes)
+