diff --git a/nixos/modules/services/monitoring/prometheus/exporters/mqtt.nix b/nixos/modules/services/monitoring/prometheus/exporters/mqtt.nix
index d1d6fcf6e2de..f9fbb3d323da 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/mqtt.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/mqtt.nix
@@ -115,7 +115,7 @@ in
       KEEP_FULL_TOPIC = toConfigBoolean cfg.keepFullTopic;
       LOG_LEVEL = cfg.logLevel;
       LOG_MQTT_MESSAGE = toConfigBoolean cfg.logMqttMessage;
-      MQTT_IGNORED_TOPIC = toConfigList cfg.mqttIgnoredTopics;
+      MQTT_IGNORED_TOPICS = toConfigList cfg.mqttIgnoredTopics;
       MQTT_ADDRESS = cfg.mqttAddress;
       MQTT_PORT = toString cfg.mqttPort;
       MQTT_TOPIC = cfg.mqttTopic;