diff --git a/jdav_web/mailer/admin.py b/jdav_web/mailer/admin.py
index ffb476a..9e9675d 100644
--- a/jdav_web/mailer/admin.py
+++ b/jdav_web/mailer/admin.py
@@ -2,6 +2,8 @@ from django.contrib import admin
 from django.contrib.admin import helpers
 from django.utils.translation import ugettext_lazy as _
 from django.shortcuts import render
+from django.db import models
+from django import forms
 
 from .models import Message
 
@@ -10,6 +12,9 @@ class MessageAdmin(admin.ModelAdmin):
     """Message creation view"""
     list_display = ('subject', 'from_addr', 'get_groups', 'sent')
     change_form_template = "mailer/change_form.html"
+    formfield_overrides = {
+        models.ManyToManyField: {'widget': forms.CheckboxSelectMultiple}
+    }
 
     actions = ['send_message']
 
diff --git a/jdav_web/members/admin.py b/jdav_web/members/admin.py
index 0394801..ebd62a4 100644
--- a/jdav_web/members/admin.py
+++ b/jdav_web/members/admin.py
@@ -11,7 +11,7 @@ from django import forms
 from django.contrib import admin
 from django.contrib.admin import DateFieldListFilter
 from django.utils.translation import ugettext_lazy as translate
-from django.db.models import TextField
+from django.db.models import TextField, ManyToManyField
 from django.forms import Textarea
 
 from .models import (Member, Group, MemberList, MemberOnList, Klettertreff,
@@ -25,6 +25,9 @@ class MemberAdmin(admin.ModelAdmin):
     list_display = ('name', 'street', 'town', 'phone_number',
             'phone_number_parents', 'birth_date', 'gets_newsletter', 'get_group', 'comments')
     list_filter = ('group', 'gets_newsletter')
+    formfield_overrides = {
+        ManyToManyField: {'widget': forms.CheckboxSelectMultiple}
+    }
 
 
 class GroupAdmin(admin.ModelAdmin):
@@ -125,6 +128,7 @@ class MemberListAdmin(admin.ModelAdmin):
 
             return response
 
+
 class KlettertreffAdminForm(forms.ModelForm):
     class Meta:
         model = Klettertreff
@@ -145,6 +149,10 @@ class KlettertreffAdmin(admin.ModelAdmin):
     inlines = [KlettertreffAttendeeInline]
     list_display = ['__str__', 'date', 'get_jugendleiter']
     list_filter = [('date', DateFieldListFilter)]
+    formfield_overrides = {
+        ManyToManyField: {'widget': forms.CheckboxSelectMultiple}
+    }
+
 
 admin.site.register(Member, MemberAdmin)
 admin.site.register(Group, GroupAdmin)