How to modify Django admin filter’s title

You will need to have a custom filter class, but you can actually implement a custom filter class factory that you can use everywhere you just need a filter with a custom title:

from django.contrib import admin

def custom_titled_filter(title):
    class Wrapper(admin.FieldListFilter):
        def __new__(cls, *args, **kwargs):
            instance = admin.FieldListFilter.create(*args, **kwargs)
            instance.title = title
            return instance
    return Wrapper

After that in your ModelAdmin class:

list_filter = (
    ('fieldname', custom_titled_filter('My Custom Title')),
    'plain_field',
    ...
)

(Note how the custom filter is not just a field name, but a tuple of (field_name, CustomFilterClass), you’re just getting your CustomFilterClass from your custom_titled_filter() factory)