diff --git a/zerver/migrations/0148_max_invites_forget_default.py b/zerver/migrations/0148_max_invites_forget_default.py
new file mode 100644
index 0000000000..297faf498a
--- /dev/null
+++ b/zerver/migrations/0148_max_invites_forget_default.py
@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2018-02-10 02:59
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('zerver', '0147_realm_disallow_disposable_email_addresses'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='realm',
+            name='max_invites',
+            field=models.IntegerField(null=True, db_column='max_invites'),
+        ),
+        migrations.RenameField(
+            model_name='realm',
+            old_name='max_invites',
+            new_name='_max_invites',
+        ),
+    ]
diff --git a/zerver/models.py b/zerver/models.py
index f51e257cc9..1d8855cbd4 100644
--- a/zerver/models.py
+++ b/zerver/models.py
@@ -185,8 +185,7 @@ class Realm(models.Model):
     authentication_methods = BitField(flags=AUTHENTICATION_FLAGS,
                                       default=2**31 - 1)  # type: BitHandler
     waiting_period_threshold = models.PositiveIntegerField(default=0)  # type: int
-    DEFAULT_MAX_INVITES = 100
-    max_invites = models.IntegerField(default=DEFAULT_MAX_INVITES)  # type: int
+    _max_invites = models.IntegerField(null=True, db_column='max_invites')  # type: int
     message_visibility_limit = models.IntegerField(null=True)  # type: int
     # See upload_quota_bytes; don't interpret upload_quota_gb directly.
     upload_quota_gb = models.IntegerField(null=True)  # type: Optional[int]
@@ -285,6 +284,16 @@ class Realm(models.Model):
             return self.signup_notifications_stream
         return None
 
+    @property
+    def max_invites(self) -> int:
+        if self._max_invites is None:
+            return settings.INVITES_DEFAULT_REALM_DAILY_MAX
+        return self._max_invites
+
+    @max_invites.setter
+    def max_invites(self, value: int) -> None:
+        self._max_invites = value
+
     def upload_quota_bytes(self) -> Optional[int]:
         if self.upload_quota_gb is None:
             return None
diff --git a/zerver/tests/test_signup.py b/zerver/tests/test_signup.py
index aa684cd075..5963782487 100644
--- a/zerver/tests/test_signup.py
+++ b/zerver/tests/test_signup.py
@@ -647,6 +647,15 @@ earl-test@zulip.com""", ["Denmark"]))
         self.check_sent_emails(["bob-test@zulip.com", "carol-test@zulip.com",
                                 "dave-test@zulip.com", "earl-test@zulip.com"])
 
+    def test_max_invites_model(self) -> None:
+        realm = get_realm("zulip")
+        self.assertEqual(realm.max_invites, settings.INVITES_DEFAULT_REALM_DAILY_MAX)
+        realm.max_invites = 3
+        realm.save()
+        self.assertEqual(get_realm("zulip").max_invites, 3)
+        realm.max_invites = settings.INVITES_DEFAULT_REALM_DAILY_MAX
+        realm.save()
+
     def test_invite_too_many_users(self) -> None:
         # Only a light test of this pathway; e.g. doesn't test that
         # the limit gets reset after 24 hours
diff --git a/zproject/settings.py b/zproject/settings.py
index ef90645d95..1ec266c4f5 100644
--- a/zproject/settings.py
+++ b/zproject/settings.py
@@ -306,6 +306,9 @@ DEFAULT_SETTINGS.update({
     #
     # A non-admin user who's joined an open realm this recently can't invite at all.
     'INVITES_MIN_USER_AGE_DAYS': 3,
+    # Default for a realm's `max_invites`; which applies per day,
+    # and only applies if OPEN_REALM_CREATION is true.
+    'INVITES_DEFAULT_REALM_DAILY_MAX': 100,
 
     # Controls for which links are published in portico footers/headers/etc.
     'EMAIL_DELIVERER_DISABLED': False,