diff --git a/core/dictgen/res/DictSelectionReader.h b/core/dictgen/res/DictSelectionReader.h
index 8dda49afa922699b4aba1fd8b4c9dc4ae4b08167..52921d62373dead89745fe5b30aa574c8349aa88 100644
--- a/core/dictgen/res/DictSelectionReader.h
+++ b/core/dictgen/res/DictSelectionReader.h
@@ -234,8 +234,10 @@ ROOT::Selection::NS::C.
  * [...]
  *
  **/
-class DictSelectionReader
-      : public clang::RecursiveASTVisitor<DictSelectionReader> {
+namespace ROOT {
+namespace Internal {
+
+class DictSelectionReader : public clang::RecursiveASTVisitor<DictSelectionReader> {
 public:
    /// Take the selection rules as input (for consistency w/ other selector
    /// interfaces)
@@ -302,5 +304,7 @@ private:
    bool fIsFirstPass; ///< Keep trance of the number of passes through the AST
    ROOT::TMetaUtils::TNormalizedCtxt &fNormCtxt; /// < The reference to the normalized context
 };
+}
+}
 
 #endif
diff --git a/core/dictgen/src/DictSelectionReader.cxx b/core/dictgen/src/DictSelectionReader.cxx
index dba6283309acc1dab983284405d1fe56cadf36b2..38dd4c8b4c6e0e5d8acee99deb7e3df13868d9a1 100644
--- a/core/dictgen/src/DictSelectionReader.cxx
+++ b/core/dictgen/src/DictSelectionReader.cxx
@@ -14,6 +14,9 @@
 #include <iostream>
 #include <sstream>
 
+namespace ROOT {
+namespace Internal {
+
 ////////////////////////////////////////////////////////////////////////////////
 
 DictSelectionReader::DictSelectionReader(cling::Interpreter &interp, SelectionRules &selectionRules,
@@ -412,3 +415,6 @@ inline void DictSelectionReader::GetPointeeType(std::string &typeName)
       typeName = typeName.substr(0, typeName.size() - 1);
    }
 }
+
+}
+}
diff --git a/core/dictgen/src/rootcling_impl.cxx b/core/dictgen/src/rootcling_impl.cxx
index c90975e043f54201831bda4de781adbb2ef80adf..4a6271c5193e89f9483e074c0415abb8da94038e 100644
--- a/core/dictgen/src/rootcling_impl.cxx
+++ b/core/dictgen/src/rootcling_impl.cxx
@@ -4610,7 +4610,7 @@ int RootClingMain(int argc,
    // Select using DictSelection
    const unsigned int selRulesInitialSize = selectionRules.Size();
    if (dictSelection && !onepcm)
-      DictSelectionReader dictSelReader(interp, selectionRules, CI->getASTContext(), normCtxt);
+      ROOT::Internal::DictSelectionReader dictSelReader(interp, selectionRules, CI->getASTContext(), normCtxt);
 
    bool dictSelRulesPresent = selectionRules.Size() > selRulesInitialSize;