diff --git a/note_kfet/middlewares.py b/note_kfet/middlewares.py
index f545d839..cf99c99f 100644
--- a/note_kfet/middlewares.py
+++ b/note_kfet/middlewares.py
@@ -142,3 +142,17 @@ class TurbolinksMiddleware(object):
                     location = request.session.pop('_turbolinks_redirect_to')
                     response['Turbolinks-Location'] = location
         return response
+
+
+class ClacksMiddleware(object):
+    """
+    Add Clacks Overhead header on each response.
+    See https://www.gnuterrypratchett.com/
+    """
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        response = self.get_response(request)
+        response['X-Clacks-Overhead'] = 'GNU Terry Pratchett'
+        return response
diff --git a/note_kfet/settings/base.py b/note_kfet/settings/base.py
index 1cbf6ed7..bd6677d3 100644
--- a/note_kfet/settings/base.py
+++ b/note_kfet/settings/base.py
@@ -82,6 +82,7 @@ MIDDLEWARE = [
     'note_kfet.middlewares.SessionMiddleware',
     'note_kfet.middlewares.LoginByIPMiddleware',
     'note_kfet.middlewares.TurbolinksMiddleware',
+    'note_kfet.middlewares.ClacksMiddleware',
 ]
 
 ROOT_URLCONF = 'note_kfet.urls'