diff --git a/requirements.txt b/requirements.txt
index 065eb2d..5999c00 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
 slixmpp
 omemo
+omemo-backend-signal
diff --git a/setup.py b/setup.py
index 976e834..b0bbf00 100755
--- a/setup.py
+++ b/setup.py
@@ -71,6 +71,6 @@ setup(
     url='https://lab.louiz.org/poezio/slixmpp-omemo',
     license='GPLv3',
     platforms=['any'],
-    install_requires=['slixmpp', 'omemo'],
+    install_requires=['slixmpp', 'omemo', 'omemo-backend-signal'],
     classifiers=CLASSIFIERS,
 )