diff --git a/roles/custom/matrix-tuwunel/defaults/main.yml b/roles/custom/matrix-tuwunel/defaults/main.yml
index 7bc6e1d5b..e238d5fe9 100644
--- a/roles/custom/matrix-tuwunel/defaults/main.yml
+++ b/roles/custom/matrix-tuwunel/defaults/main.yml
@@ -265,6 +265,12 @@ matrix_tuwunel_config_enable_policy_servers: false
 # signature-fetches against a room's policy server.
 matrix_tuwunel_config_policy_server_request_timeout: 5
 
+# Whether tuwunel evaluates MSC3664 related-event push conditions itself.
+# The default `.im.nheko.msc3664.reply` rule needs this to affect notification counts and pusher delivery.
+# Clients implementing MSC3664 evaluate the rule locally either way.
+# Enabling it costs an extra event lookup for every event carrying a relation.
+matrix_tuwunel_config_msc3664_related_event_match: false
+
 # Outgoing presence is heavy on CPU and network and almost no clients use it. Off by default.
 matrix_tuwunel_config_allow_outgoing_presence: false
 
diff --git a/roles/custom/matrix-tuwunel/templates/tuwunel.toml.j2 b/roles/custom/matrix-tuwunel/templates/tuwunel.toml.j2
index b11a7ce6e..a1c381039 100644
--- a/roles/custom/matrix-tuwunel/templates/tuwunel.toml.j2
+++ b/roles/custom/matrix-tuwunel/templates/tuwunel.toml.j2
@@ -61,6 +61,8 @@ ip_range_denylist = {{ matrix_tuwunel_config_ip_range_denylist | to_json }}
 enable_policy_servers = {{ matrix_tuwunel_config_enable_policy_servers | to_json }}
 policy_server_request_timeout = {{ matrix_tuwunel_config_policy_server_request_timeout }}
 
+msc3664_related_event_match = {{ matrix_tuwunel_config_msc3664_related_event_match | to_json }}
+
 allow_outgoing_presence = {{ matrix_tuwunel_config_allow_outgoing_presence | to_json }}
 
 {% if matrix_tuwunel_config_url_preview_domain_contains_allowlist | length > 0 %}