diff --git a/roles/matrix-synapse/defaults/main.yml b/roles/matrix-synapse/defaults/main.yml
index bf4a4359..fbf39778 100644
--- a/roles/matrix-synapse/defaults/main.yml
+++ b/roles/matrix-synapse/defaults/main.yml
@@ -296,6 +296,12 @@ matrix_synapse_room_list_publication_rules:
 
 matrix_synapse_default_room_version: "4"
 
+# Controls the Synapse `spam_checker` setting.
+#
+# If a spam-checker extension is enabled, this variable's value is set automatically by the playbook during runtime.
+# If not, you can also control its value manually.
+matrix_synapse_spam_checker: ~
+
 # Default Synapse configuration template which covers the generic use case.
 # You can customize it by controlling the various variables inside it.
 #
diff --git a/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2 b/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2
index 220e62cd..91f371a2 100644
--- a/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2
+++ b/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2
@@ -1319,7 +1319,7 @@ push:
 #  module: "my_custom_project.SuperSpamChecker"
 #  config:
 #    example_option: 'things'
-
+spam_checker: {{ matrix_synapse_spam_checker|to_json }}
 
 # Uncomment to allow non-server-admin users to create groups on this server
 #