diff --git a/Reconstruction/tauRecTools/Root/BDTHelper.cxx b/Reconstruction/tauRecTools/Root/BDTHelper.cxx
index 1623f035d27863029c40ce0ef39ef84c91b576a6..a5f3261489a1372696a1de3802b13d4afb82ff97 100644
--- a/Reconstruction/tauRecTools/Root/BDTHelper.cxx
+++ b/Reconstruction/tauRecTools/Root/BDTHelper.cxx
@@ -7,6 +7,7 @@
 #include "TFile.h"
 #include "TTree.h"
 #include "TObjArray.h"
+#include "TObjString.h"
 
 namespace tauRecTools {