diff --git a/src/gmm/mle-diag-gmm.h b/src/gmm/mle-diag-gmm.h
index d41d36489bf..3763943a89b 100644
--- a/src/gmm/mle-diag-gmm.h
+++ b/src/gmm/mle-diag-gmm.h
@@ -93,7 +93,7 @@ struct MapDiagGmmOptions {
   void Register(OptionsItf *opts) {
     opts->Register("mean-tau", &mean_tau,
                    "Tau value for updating means.");
-    opts->Register("variance-tau", &mean_tau,
+    opts->Register("variance-tau", &variance_tau,
                    "Tau value for updating variances (note: only relevant if "
                    "update-flags contains \"v\".");
     opts->Register("weight-tau", &weight_tau,