diff --git a/judge/views/register.py b/judge/views/register.py
index 67c1c4f..b87c1e4 100644
--- a/judge/views/register.py
+++ b/judge/views/register.py
@@ -40,6 +40,16 @@ class CustomRegistrationForm(RegistrationForm):
     if ReCaptchaField is not None:
         captcha = ReCaptchaField(widget=ReCaptchaWidget())
 
+    def clean_organizations(self):
+        organizations = self.cleaned_data.get('organizations') or []
+        max_orgs = settings.DMOJ_USER_MAX_ORGANIZATION_COUNT
+
+        if sum(org.is_open for org in organizations) > max_orgs:
+            raise forms.ValidationError(
+                _('You may not be part of more than {count} public organizations.').format(count=max_orgs))
+
+        return self.cleaned_data['organizations']
+
     def clean_email(self):
         if User.objects.filter(email=self.cleaned_data['email']).exists():
             raise forms.ValidationError(gettext('The email address "%s" is already taken. Only one registration '
@@ -66,6 +76,7 @@ class RegistrationView(OldRegistrationView):
         kwargs['TIMEZONE_BG'] = settings.TIMEZONE_BG if tzmap else '#4E7CAD'
         kwargs['password_validators'] = get_default_password_validators()
         kwargs['tos_url'] = settings.TERMS_OF_SERVICE_URL
+        print(kwargs['form'].errors)
         return super(RegistrationView, self).get_context_data(**kwargs)
 
     def register(self, form):
diff --git a/templates/registration/registration_form.html b/templates/registration/registration_form.html
index 220aa43..528145b 100644
--- a/templates/registration/registration_form.html
+++ b/templates/registration/registration_form.html
@@ -185,6 +185,9 @@
 
             <div class="block-header">{{ _('Affiliated organizations') }}</div>
             {{ form.organizations }}
+            {% if form.organizations.errors %}
+                <div class="form-field-error">{{ form.organizations.errors }}</div>
+            {% endif %}
 
             {% if form.newsletter %}
                 <div style="padding-top: 0.5em;">{{ form.newsletter }}