diff --git a/rattail_harvest/importing/harvest.py b/rattail_harvest/importing/harvest.py
index 695d04d..3d5abfd 100644
--- a/rattail_harvest/importing/harvest.py
+++ b/rattail_harvest/importing/harvest.py
@@ -110,6 +110,15 @@ class HarvestUserImporter(FromHarvest, rattail_harvest_importing.model.HarvestUs
     def get_host_objects(self):
         return self.webapi.get_users()['users']
 
+    def normalize_host_object(self, user):
+        data = super(HarvestUserImporter, self).normalize_host_object(user)
+        if data:
+
+            if data['telephone'] == '':
+                data['telephone'] = None
+
+            return data
+
 
 class HarvestClientImporter(FromHarvest, rattail_harvest_importing.model.HarvestClientImporter):
     """