get_context_data in Django CBVs

get_context_data() is a CBV method for passing additional data to a template.

Basic usage

from django.views.generic import ListView
from .models import Task, Project

class TaskListView(ListView):
    model = Task
    template_name = 'tasks/task_list.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['projects'] = Project.objects.all()
        context['total_count'] = Task.objects.count()
        context['page_title'] = 'All tasks'
        return context

In the template

<h1>{{ page_title }}</h1>
<p>Total tasks: {{ total_count }}</p>

<select name="project">
  {% for project in projects %}
    <option value="{{ project.pk }}">{{ project.name }}</option>
  {% endfor %}
</select>

DetailView + additional data

class TaskDetailView(DetailView):
    model = Task

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['related_tasks'] = Task.objects.filter(
            project=self.object.project
        ).exclude(pk=self.object.pk)[:5]
        context['can_edit'] = self.object.owner == self.request.user
        return context

Data from the request

def get_context_data(self, **kwargs):
    context = super().get_context_data(**kwargs)
    context['search_query'] = self.request.GET.get('q', '')
    context['active_filter'] = self.request.GET.get('status', 'all')
    return context

Important: always call super()

def get_context_data(self, **kwargs):
    context = super().get_context_data(**kwargs)  # base context (object_list, etc.)
    context['extra'] = 'value'
    return context

Without super() you will lose object_list, object, view, and other standard template variables.