diff --git a/homeassistant/components/caldav/manifest.json b/homeassistant/components/caldav/manifest.json
index e0d598e6493..5c1334c8029 100644
--- a/homeassistant/components/caldav/manifest.json
+++ b/homeassistant/components/caldav/manifest.json
@@ -6,5 +6,5 @@
   "documentation": "https://www.home-assistant.io/integrations/caldav",
   "iot_class": "cloud_polling",
   "loggers": ["caldav", "vobject"],
-  "requirements": ["caldav==1.3.9"]
+  "requirements": ["caldav==1.3.9", "icalendar==6.1.0"]
 }
diff --git a/requirements_all.txt b/requirements_all.txt
index b194f249770..65d9ca63667 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -1177,6 +1177,9 @@ ibmiotf==0.3.4
 # homeassistant.components.local_todo
 ical==8.2.0
 
+# homeassistant.components.caldav
+icalendar==6.1.0
+
 # homeassistant.components.ping
 icmplib==3.0
 
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 2576bdeedf7..b4d0fbf0432 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -997,6 +997,9 @@ ibeacon-ble==1.2.0
 # homeassistant.components.local_todo
 ical==8.2.0
 
+# homeassistant.components.caldav
+icalendar==6.1.0
+
 # homeassistant.components.ping
 icmplib==3.0