diff --git a/mayan/apps/authentication/auth/email_auth_backend.py b/mayan/apps/authentication/auth/email_auth_backend.py
index 3caf5f0804..043126df4a 100644
--- a/mayan/apps/authentication/auth/email_auth_backend.py
+++ b/mayan/apps/authentication/auth/email_auth_backend.py
@@ -13,7 +13,7 @@ class EmailAuthBackend(ModelBackend):
     def authenticate(self, email=None, password=None):
         UserModel = get_user_model()
         try:
-            user = UserModel.objects.get(email=email)
+            user = UserModel.on_organization.get(email=email)
             if user.check_password(password):
                 return user
         except UserModel.DoesNotExist:
diff --git a/mayan/apps/authentication/auth/model_auth_backend.py b/mayan/apps/authentication/auth/model_auth_backend.py
new file mode 100644
index 0000000000..575c65c6ea
--- /dev/null
+++ b/mayan/apps/authentication/auth/model_auth_backend.py
@@ -0,0 +1,20 @@
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.contrib.auth import get_user_model
+from django.contrib.auth.backends import ModelBackend
+
+
+class UsernameModelBackend(ModelBackend):
+    def authenticate(self, username=None, password=None, **kwargs):
+        UserModel = get_user_model()
+        if username is None:
+            username = kwargs.get(UserModel.USERNAME_FIELD)
+        try:
+            user = UserModel.on_organization.get(username=username)
+            if user.check_password(password):
+                return user
+        except UserModel.DoesNotExist:
+            # Run the default password hasher once to reduce the timing
+            # difference between an existing and a non-existing user (#20760).
+            UserModel().set_password(password)
diff --git a/mayan/apps/document_states/models.py b/mayan/apps/document_states/models.py
index f4035ed846..09fc7cf345 100644
--- a/mayan/apps/document_states/models.py
+++ b/mayan/apps/document_states/models.py
@@ -2,7 +2,7 @@ from __future__ import unicode_literals
 
 import logging
 
-from django.contrib.auth.models import User
+from django.conf import settings
 from django.core.urlresolvers import reverse
 from django.db import IntegrityError, models
 from django.utils.encoding import python_2_unicode_compatible
@@ -186,7 +186,7 @@ class WorkflowInstanceLogEntry(models.Model):
     transition = models.ForeignKey(
         WorkflowTransition, verbose_name=_('Transition')
     )
-    user = models.ForeignKey(User, verbose_name=_('User'))
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, verbose_name=_('User'))
     comment = models.TextField(blank=True, verbose_name=_('Comment'))
 
     def __str__(self):
diff --git a/mayan/apps/documents/models.py b/mayan/apps/documents/models.py
index 0142628e36..712c74b08e 100644
--- a/mayan/apps/documents/models.py
+++ b/mayan/apps/documents/models.py
@@ -5,7 +5,7 @@ import hashlib
 import logging
 import uuid
 
-from django.contrib.auth.models import User
+from django.conf import settings
 from django.core.exceptions import PermissionDenied
 from django.core.files import File
 from django.core.urlresolvers import reverse
@@ -806,7 +806,7 @@ class RecentDocument(models.Model):
     a given user
     """
     user = models.ForeignKey(
-        User, db_index=True, editable=False, verbose_name=_('User')
+        settings.AUTH_USER_MODEL, db_index=True, editable=False, verbose_name=_('User')
     )
     document = models.ForeignKey(
         Document, editable=False, verbose_name=_('Document')
@@ -822,7 +822,7 @@ class RecentDocument(models.Model):
 
     def natural_key(self):
         return self.document.natural_key() + self.user.natural_key()
-    natural_key.dependencies = ['documents.Document', 'auth.User']
+    natural_key.dependencies = ['documents.Document', 'user_management.User']
 
     class Meta:
         ordering = ('-datetime_accessed',)
diff --git a/mayan/apps/dynamic_search/models.py b/mayan/apps/dynamic_search/models.py
index 9afc0c97dc..b3ee98b156 100644
--- a/mayan/apps/dynamic_search/models.py
+++ b/mayan/apps/dynamic_search/models.py
@@ -3,7 +3,7 @@ from __future__ import unicode_literals
 import urllib
 import urlparse
 
-from django.contrib.auth.models import User
+from django.conf import settings
 from django.core.urlresolvers import reverse
 from django.db import models
 from django.utils.encoding import (
@@ -20,7 +20,9 @@ class RecentSearch(models.Model):
     Keeps a list of the [n] most recent search keywords for a given user
     """
 
-    user = models.ForeignKey(User, editable=False, verbose_name=_('User'))
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL, editable=False, verbose_name=_('User')
+    )
     query = models.TextField(editable=False, verbose_name=_('Query'))
     datetime_created = models.DateTimeField(
         auto_now=True, db_index=True, verbose_name=_('Datetime created')
diff --git a/mayan/apps/folders/models.py b/mayan/apps/folders/models.py
index 4db0235042..8d8dca0135 100644
--- a/mayan/apps/folders/models.py
+++ b/mayan/apps/folders/models.py
@@ -1,5 +1,6 @@
 from __future__ import absolute_import, unicode_literals
 
+from django.conf import settings
 from django.contrib.auth.models import User
 from django.core.exceptions import PermissionDenied
 from django.core.urlresolvers import reverse
@@ -26,7 +27,7 @@ class Folder(models.Model):
     label = models.CharField(
         db_index=True, max_length=128, verbose_name=_('Label')
     )
-    user = models.ForeignKey(User, verbose_name=_('User'))
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, verbose_name=_('User'))
     datetime_created = models.DateTimeField(
         auto_now_add=True, verbose_name=_('Datetime created')
     )
diff --git a/mayan/apps/user_management/admin.py b/mayan/apps/user_management/admin.py
new file mode 100644
index 0000000000..989fd6e179
--- /dev/null
+++ b/mayan/apps/user_management/admin.py
@@ -0,0 +1,17 @@
+from django import forms
+from django.contrib import admin
+from django.contrib.auth.models import Group
+from django.contrib.auth.admin import UserAdmin
+from django.contrib.auth.forms import ReadOnlyPasswordHashField
+
+from user_management.models import MayanUser
+
+
+@admin.register(MayanUser)
+class MayanUserAdmin(UserAdmin):
+    list_display = ('organization',) + UserAdmin.list_display
+    list_display_links = ('username',)
+    list_filter = UserAdmin.list_filter + ('organization',)
+    ordering = ('organization',) + UserAdmin.ordering
+    fieldsets = UserAdmin.fieldsets
+    fieldsets[1][1]['fields'] = ('organization',) + fieldsets[1][1]['fields']
diff --git a/mayan/apps/user_management/api_views.py b/mayan/apps/user_management/api_views.py
index d4cb4e8fce..945267fc5a 100644
--- a/mayan/apps/user_management/api_views.py
+++ b/mayan/apps/user_management/api_views.py
@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
-from django.contrib.auth.models import Group, User
+from django.contrib.auth import get_user_model
+from django.contrib.auth.models import Group
 
 from rest_framework import generics
 
@@ -83,7 +84,7 @@ class APIUserListView(generics.ListCreateAPIView):
     mayan_object_permissions = {'GET': (permission_user_view,)}
     mayan_view_permissions = {'POST': (permission_user_create,)}
     permission_classes = (MayanPermission,)
-    queryset = User.objects.all()
+    queryset = get_user_model().objects.all()
     serializer_class = UserSerializer
 
     def get(self, *args, **kwargs):
@@ -108,7 +109,7 @@ class APIUserView(generics.RetrieveUpdateDestroyAPIView):
         'DELETE': (permission_user_delete,)
     }
     permission_classes = (MayanPermission,)
-    queryset = User.objects.all()
+    queryset = get_user_model().objects.all()
     serializer_class = UserSerializer
 
     def delete(self, *args, **kwargs):
diff --git a/mayan/apps/user_management/migrations/0001_initial.py b/mayan/apps/user_management/migrations/0001_initial.py
new file mode 100644
index 0000000000..41ab1b5f3c
--- /dev/null
+++ b/mayan/apps/user_management/migrations/0001_initial.py
@@ -0,0 +1,43 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import django.utils.timezone
+import django.core.validators
+import organizations.shortcuts
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('auth', '0001_initial'),
+        ('organizations', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='MayanUser',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('password', models.CharField(max_length=128, verbose_name='password')),
+                ('last_login', models.DateTimeField(default=django.utils.timezone.now, verbose_name='last login')),
+                ('is_superuser', models.BooleanField(default=False, help_text='Designates that this user has all permissions without explicitly assigning them.', verbose_name='superuser status')),
+                ('username', models.CharField(help_text='Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.', unique=True, max_length=30, verbose_name='username', validators=[django.core.validators.RegexValidator('^[\\w.@+-]+$', 'Enter a valid username.', 'invalid')])),
+                ('first_name', models.CharField(max_length=30, verbose_name='first name', blank=True)),
+                ('last_name', models.CharField(max_length=30, verbose_name='last name', blank=True)),
+                ('email', models.EmailField(max_length=75, verbose_name='email address', blank=True)),
+                ('is_staff', models.BooleanField(default=False, help_text='Designates whether the user can log into this admin site.', verbose_name='staff status')),
+                ('is_active', models.BooleanField(default=True, help_text='Designates whether this user should be treated as active. Unselect this instead of deleting accounts.', verbose_name='active')),
+                ('date_joined', models.DateTimeField(default=django.utils.timezone.now, verbose_name='date joined')),
+                ('groups', models.ManyToManyField(related_query_name='user', related_name='user_set', to='auth.Group', blank=True, help_text='The groups this user belongs to. A user will get all permissions granted to each of his/her group.', verbose_name='groups')),
+                ('organization', models.ForeignKey(default=organizations.shortcuts.get_current_organization, to='organizations.Organization')),
+                ('user_permissions', models.ManyToManyField(related_query_name='user', related_name='user_set', to='auth.Permission', blank=True, help_text='Specific permissions for this user.', verbose_name='user permissions')),
+            ],
+            options={
+                'abstract': False,
+                'verbose_name': 'user',
+                'verbose_name_plural': 'users',
+            },
+            bases=(models.Model,),
+        ),
+    ]
diff --git a/mayan/apps/user_management/migrations/__init__.py b/mayan/apps/user_management/migrations/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/mayan/apps/user_management/models.py b/mayan/apps/user_management/models.py
new file mode 100644
index 0000000000..6c3b77ff9c
--- /dev/null
+++ b/mayan/apps/user_management/models.py
@@ -0,0 +1,20 @@
+from __future__ import unicode_literals
+
+from django.contrib.auth.models import AbstractUser, UserManager
+from django.core.urlresolvers import reverse
+from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
+from django.utils.translation import ugettext_lazy as _
+
+from organizations.models import Organization
+from organizations.managers import CurrentOrganizationManager
+from organizations.shortcuts import get_current_organization
+
+
+class MayanUser(AbstractUser):
+    organization = models.ForeignKey(
+        Organization, default=get_current_organization
+    )
+
+    objects = UserManager()
+    on_organization = CurrentOrganizationManager()
diff --git a/mayan/apps/user_management/views.py b/mayan/apps/user_management/views.py
index 5ac4cf73cf..d90cad59ac 100644
--- a/mayan/apps/user_management/views.py
+++ b/mayan/apps/user_management/views.py
@@ -3,7 +3,7 @@ from __future__ import absolute_import, unicode_literals
 from django.conf import settings
 from django.contrib import messages
 from django.contrib.auth import get_user_model
-from django.contrib.auth.models import Group, User
+from django.contrib.auth.models import Group
 from django.core.urlresolvers import reverse, reverse_lazy
 from django.http import HttpResponseRedirect
 from django.shortcuts import get_object_or_404, render_to_response
@@ -86,7 +86,7 @@ class GroupMembersView(AssignRemoveView):
 
     def left_list(self):
         return AssignRemoveView.generate_choices(
-            User.objects.exclude(
+            get_user_model().objects.exclude(
                 groups=self.get_object()
             ).exclude(is_staff=True).exclude(is_superuser=True)
         )
@@ -131,7 +131,7 @@ class UserGroupsView(AssignRemoveView):
         }
 
     def get_object(self):
-        return get_object_or_404(User, pk=self.kwargs['pk'])
+        return get_object_or_404(get_user_model(), pk=self.kwargs['pk'])
 
     def left_list(self):
         return AssignRemoveView.generate_choices(
diff --git a/mayan/settings/base.py b/mayan/settings/base.py
index f5fc541218..b839d7a0b6 100644
--- a/mayan/settings/base.py
+++ b/mayan/settings/base.py
@@ -288,3 +288,8 @@ TIMEZONE_COOKIE_NAME = 'django_timezone'
 TIMEZONE_SESSION_KEY = 'django_timezone'
 # ------ Organization -------
 ORGANIZATION_ID = 1
+# ------ User model --------
+AUTH_USER_MODEL = 'user_management.MayanUser'
+# ------- Authentication -------
+AUTHENTICATION_BACKENDS = ('authentication.auth.model_auth_backend.UsernameModelBackend',)
+