diff --git a/accounts/migrations/0010_change_username_validator.py b/accounts/migrations/0010_change_username_validator.py
new file mode 100644
index 0000000000000000000000000000000000000000..26f001c3e66a7b9ac6bac85cdb543f99e913b9e7
--- /dev/null
+++ b/accounts/migrations/0010_change_username_validator.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.4 on 2017-04-12 08:55
+from __future__ import unicode_literals
+
+import django.contrib.auth.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('accounts', '0009_user_git_auth_token_hash'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='user',
+            name='username',
+            field=models.CharField(error_messages={'unique': 'A user with that username already exists.'}, help_text='Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.', max_length=30, unique=True, validators=[django.contrib.auth.validators.ASCIIUsernameValidator()], verbose_name='username'),
+        ),
+    ]
diff --git a/accounts/models.py b/accounts/models.py
index 915e0945b1a9ee9097e9e4b03461b990fb1218cf..51c97f38d66f1ee9290dbdbdaef9845a40ba0fbf 100644
--- a/accounts/models.py
+++ b/accounts/models.py
@@ -30,7 +30,7 @@ from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin
 from django.utils.translation import ugettext_lazy as _, pgettext_lazy
 from django.utils import timezone
 from django.contrib.auth.models import UserManager
-from django.core import validators
+from django.contrib.auth.validators import ASCIIUsernameValidator
 
 from course.constants import USER_STATUS_CHOICES
 
@@ -44,13 +44,7 @@ class User(AbstractBaseUser, PermissionsMixin):
         unique=True,
         help_text=_(
             'Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.'),
-        validators=[
-            validators.RegexValidator(
-                r'^[\w.@+-]+$',
-                _('Enter a valid username. This value may contain only '
-                  'letters, numbers ' 'and @/./+/-/_ characters.')
-            ),
-        ],
+        validators=[ASCIIUsernameValidator()],
         error_messages={
             'unique': _("A user with that username already exists."),
         },
@@ -159,8 +153,6 @@ class User(AbstractBaseUser, PermissionsMixin):
             Returns the first_name plus the last_name, with a space in
             between.
             """
-            if force_verbose_blank:
-                first_name
             return '%s %s' % (
                 verbose_blank(first_name), verbose_blank(last_name))
 
diff --git a/course/auth.py b/course/auth.py
index 348c2e3817e3df457ed49882e3f6e5dea555e5b7..84fe455bdd1eb9473e843c23e272502be16c809e 100644
--- a/course/auth.py
+++ b/course/auth.py
@@ -42,7 +42,7 @@ from django.contrib.auth.forms import \
 from django.contrib.sites.shortcuts import get_current_site
 from django.contrib.auth.decorators import user_passes_test
 from django.urls import reverse
-from django.core import validators
+from django.contrib.auth.validators import ASCIIUsernameValidator
 from django.utils.http import is_safe_url
 from django.http import HttpResponseRedirect
 from django.template.response import TemplateResponse
@@ -386,15 +386,7 @@ def sign_in_by_user_pw(request, redirect_field_name=REDIRECT_FIELD_NAME):
 class SignUpForm(StyledModelForm):
     username = forms.CharField(required=True, max_length=30,
             label=_("Username"),
-            validators=[
-                validators.RegexValidator('^[\\w.@+-]+$',
-                    string_concat(
-                        _('Enter a valid username.'), (' '),
-                        _('This value may contain only letters, '
-                          'numbers and @/./+/-/_ characters.')
-                        ),
-                    'invalid')
-                ])
+            validators=[ASCIIUsernameValidator()])
 
     class Meta:
         model = get_user_model()