diff --git a/src/OpenMesh/Core/IO/SR_binary_spec.hh b/src/OpenMesh/Core/IO/SR_binary_spec.hh
index 014c11fc..4d2b3bf3 100644
--- a/src/OpenMesh/Core/IO/SR_binary_spec.hh
+++ b/src/OpenMesh/Core/IO/SR_binary_spec.hh
@@ -330,7 +330,7 @@ struct binary< std::vector< T >, typename std::enable_if<std::is_default_constru
   typedef typename value_type::value_type elem_type;
 
   static const bool is_streamable = binary<T>::is_streamable;
-  static size_t size_of(bool _store_size = true)
+  static size_t size_of(bool /*_store_size*/ = true)
   { return IO::UnknownSize; }
 
   static size_t size_of(const value_type& _v, bool _store_size = true)
diff --git a/src/OpenMesh/Core/IO/SR_binary_vector_of_bool.hh b/src/OpenMesh/Core/IO/SR_binary_vector_of_bool.hh
index 2896bb47..70e06e3f 100644
--- a/src/OpenMesh/Core/IO/SR_binary_vector_of_bool.hh
+++ b/src/OpenMesh/Core/IO/SR_binary_vector_of_bool.hh
@@ -6,7 +6,7 @@ template <> struct binary< std::vector<bool> >
 
   static const bool is_streamable = true;
 
-  static size_t size_of(bool _store_size = true) { return UnknownSize; }
+  static size_t size_of(bool /*_store_size*/ = true) { return UnknownSize; }
   static size_t size_of(const value_type& _v, bool _store_size = true)
   {
     size_t size = _v.size() / 8 + ((_v.size() % 8)!=0);
diff --git a/src/OpenMesh/Core/IO/writer/PLYWriter.hh b/src/OpenMesh/Core/IO/writer/PLYWriter.hh
index c6fd0730..af190c13 100644
--- a/src/OpenMesh/Core/IO/writer/PLYWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/PLYWriter.hh
@@ -135,7 +135,7 @@ private:
     writeValue(_type, _out, _value);
   }
   template<typename T>
-  void writeProxy(ValueType _type, std::ostream& _out, T _value, OpenMesh::GenProg::FalseType /*_binary*/) const
+  void writeProxy(ValueType /*_type*/, std::ostream& _out, T _value, OpenMesh::GenProg::FalseType /*_binary*/) const
   {
     _out << " " << _value;
   }