diff --git a/roles/ensure-sphinx/README.rst b/roles/ensure-sphinx/README.rst
index f9b4267b4..f7a97cd18 100644
--- a/roles/ensure-sphinx/README.rst
+++ b/roles/ensure-sphinx/README.rst
@@ -1,7 +1,8 @@
 Ensure sphinx is installed
 
 Installs sphinx. Also installs any dependencies needed in the first of
-doc/requirements.txt and test-requirements.txt to be found.
+doc/requirements.txt, releasenotes/requirements.txt and
+test-requirements.txt to be found.
 
 All pip installs are done with a provided constraints file, if given.
 
diff --git a/roles/ensure-sphinx/tasks/main.yaml b/roles/ensure-sphinx/tasks/main.yaml
index 9fcc254f7..a9d318ff7 100644
--- a/roles/ensure-sphinx/tasks/main.yaml
+++ b/roles/ensure-sphinx/tasks/main.yaml
@@ -26,14 +26,14 @@
     name: find-constraints
 
 # We're not using with_first_found because the files are remote, not local.
-# We want to use doc/requirements.txt if it exists or fallback to
-# test-requirements.txt.
+# We want to use doc/requirements.txt or releasenotes/requirements.txt
+# if it exists else we want to fallback to test-requirements.txt.
 - name: Get requirements files
   shell:
     executable: /bin/bash
     chdir: "{{ zuul_work_dir }}"
     cmd: |
-      for f in doc/requirements.txt test-requirements.txt ; do
+      for f in doc/requirements.txt releasenotes/requirements.txt test-requirements.txt ; do
           if [ -f $f ] ; then
               echo $f
               break