diff --git a/doc/options.rst b/doc/options.rst
index 1aab3d08da..4dfc29156a 100644
--- a/doc/options.rst
+++ b/doc/options.rst
@@ -24,7 +24,9 @@ The other options are:
 ``--logflush``
         Clears (flushes) the log file after each write action.
 
+``--logdebug``
+        Also output debug-level messages in the log (equivalent to setting the env var QT_LOGGING_RULES="qt.*=true;*.debug=true").
+)
+
 ``--confdir`` `<dirname>`
         Uses the specified configuration directory.
-        
-