A template tag to check if an user belongs to a specific group.

group_tags.py

from django import template
from django.contrib.auth.models import Group

register = template.Library()

@register.filter(name='has_group')
def has_group(user, group_name):
    group = Group.objects.get(name=group_name)
    return True if group in user.groups.all() else False


{% if request.user|has_group:"mygroup" %}
    <p>User belongs to my group
{% else %}
    <p>User doesn't belong to mygroup</p>
{% endif %}

- See more at: http://www.abidibo.net/blog/2014/05/22/check-if-user-belongs-group-django-templates/#sthash.xY5PrSGC.dpuf

I've added try except, because if the group doesn't exist I've got error

def has_group(user, group_name):
    try:
        group = Group.objects.get(name=group_name)
        return True if group in user.groups.all() else False
    except:
        return False

I suggest using Django's ORM filter(...).first() if you want to avoid try/catch as it returns None if nothing found.

Using the walrus operator I wrote it this way:

@register.filter(name="has_group")
def has_group(user, group_name) -> bool:
    """Check if User Belongs to Given Group.

    This should be avoided as it is better to have specific permissions attached
    to models.

    Use:
    ...

    {% if request.user|has_group:"mygroup" %}
      <p>User belongs to my group
    {% else %}
      <p>User doesn't belong to mygroup</p>
    {% endif %}
    """
    if group := Group.objects.filter(name=group_name).first():
        return group in user.groups.all()

    return False

Plus there is no reason to return True if ..., in operator https://docs.python.org/3/reference/expressions.html#in returns boolean, there is no need to check if boolean, you can return just that.