diff --git a/gtsam/hybrid/HybridConditional.h b/gtsam/hybrid/HybridConditional.h
index b43bb9945..93ce33bea 100644
--- a/gtsam/hybrid/HybridConditional.h
+++ b/gtsam/hybrid/HybridConditional.h
@@ -34,8 +34,6 @@
 
 namespace gtsam {
 
-class HybridGaussianFactorGraph;
-
 /**
  * Hybrid Conditional Density
  *
diff --git a/gtsam/inference/BayesTree.h b/gtsam/inference/BayesTree.h
index 924a505a2..b4b07a357 100644
--- a/gtsam/inference/BayesTree.h
+++ b/gtsam/inference/BayesTree.h
@@ -33,7 +33,6 @@ namespace gtsam {
   // Forward declarations
   template<class FACTOR> class FactorGraph;
   template<class BAYESTREE, class GRAPH> class EliminatableClusterTree;
-  class HybridBayesTreeClique;
 
   /* ************************************************************************* */
   /** clique statistics */