diff --git a/lib/base/object.hpp b/lib/base/object.hpp
index 5a90cfa64..aae28ae88 100644
--- a/lib/base/object.hpp
+++ b/lib/base/object.hpp
@@ -27,7 +27,7 @@ class String;
 struct DebugInfo;
 class ValidationUtils;
 
-extern Value Empty;
+extern const Value Empty;
 
 #define DECLARE_PTR_TYPEDEFS(klass) \
 	typedef intrusive_ptr<klass> Ptr
diff --git a/lib/base/value.cpp b/lib/base/value.cpp
index 867c8217e..ebf3ba60b 100644
--- a/lib/base/value.cpp
+++ b/lib/base/value.cpp
@@ -13,7 +13,7 @@ template const bool& Value::Get<bool>() const;
 template const String& Value::Get<String>() const;
 template const Object::Ptr& Value::Get<Object::Ptr>() const;
 
-Value icinga::Empty;
+const Value icinga::Empty;
 
 Value::Value(std::nullptr_t)
 { }
diff --git a/lib/base/value.hpp b/lib/base/value.hpp
index 86a3b115d..6e64abb43 100644
--- a/lib/base/value.hpp
+++ b/lib/base/value.hpp
@@ -149,7 +149,7 @@ extern template const bool& Value::Get<bool>() const;
 extern template const String& Value::Get<String>() const;
 extern template const Object::Ptr& Value::Get<Object::Ptr>() const;
 
-extern Value Empty;
+extern const Value Empty;
 
 Value operator+(const Value& lhs, const char *rhs);
 Value operator+(const char *lhs, const Value& rhs);