diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index d69f1bde1795..af13408c62f9 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -1524,7 +1524,12 @@ static int pmbus_thermal_add_sensor(struct pmbus_data *pmbus_data,
 	tdata->sensor = sensor;
 	tdata->pmbus_data = pmbus_data;
 
-	tzd = devm_thermal_of_zone_register(dev, index, tdata,
+	/*
+	 * The PMBus core numbers its temperature sensors from 1, as the
+	 * hwmon tempN attributes, while the thermal core expects a 0-based
+	 * sensor index.
+	 */
+	tzd = devm_thermal_of_zone_register(dev, index - 1, tdata,
 					    &pmbus_thermal_ops);
 	/*
 	 * If CONFIG_THERMAL_OF is disabled, this returns -ENODEV,