diff --git a/src/class_diagram/visitor/translation_unit_context.cc b/src/class_diagram/visitor/translation_unit_context.cc
index ae2fe3fb..3e200753 100644
--- a/src/class_diagram/visitor/translation_unit_context.cc
+++ b/src/class_diagram/visitor/translation_unit_context.cc
@@ -196,4 +196,17 @@ translation_unit_context::get_current_package() const
     return current_package_;
 }
 
+void translation_unit_context::add_using_namespace_directive(
+    common::model::namespace_ ns)
+{
+    using_ns_declarations_[ns_.to_string()].insert(std::move(ns));
+}
+
+const std::set<common::model::namespace_> &
+translation_unit_context::using_namespace_directive(
+    const common::model::namespace_ &ns) const
+{
+    return using_ns_declarations_.at(ns.to_string());
+}
+
 }
diff --git a/src/class_diagram/visitor/translation_unit_context.h b/src/class_diagram/visitor/translation_unit_context.h
index 7775d89d..188eb1cf 100644
--- a/src/class_diagram/visitor/translation_unit_context.h
+++ b/src/class_diagram/visitor/translation_unit_context.h
@@ -78,10 +78,21 @@ public:
 
     type_safe::optional_ref<common::model::package> get_current_package() const;
 
+    void add_using_namespace_directive(common::model::namespace_ ns);
+
+    const std::set<common::model::namespace_> &using_namespace_directive(
+        const common::model::namespace_ &ns) const;
+
 private:
     // Current visitor namespace
     common::model::namespace_ ns_;
 
+    // A map of 'using namespace' declared within a given namespace scope
+    // This is necessary to properly establish the namespace of a given entity
+    // for instance in unexposed template parameters
+    std::map<std::string, std::set<common::model::namespace_>>
+        using_ns_declarations_;
+
     // Reference to the cppast entity index
     cppast::cpp_entity_index &entity_index_;
 
diff --git a/src/class_diagram/visitor/translation_unit_visitor.cc b/src/class_diagram/visitor/translation_unit_visitor.cc
index 82cfc8cf..10394118 100644
--- a/src/class_diagram/visitor/translation_unit_visitor.cc
+++ b/src/class_diagram/visitor/translation_unit_visitor.cc
@@ -187,6 +187,8 @@ void translation_unit_visitor::operator()(const cppast::cpp_entity &file)
                 if (ns_ref.get(ctx.entity_index()).size() > 0) {
                     auto full_ns = cx::util::full_name(ctx.get_namespace(),
                         ns_ref.get(ctx.entity_index()).at(0).get());
+
+                    ctx.add_using_namespace_directive(full_ns);
                 }
             }
         });
diff --git a/src/common/model/namespace.cc b/src/common/model/namespace.cc
index 8980eb12..37f42a5f 100644
--- a/src/common/model/namespace.cc
+++ b/src/common/model/namespace.cc
@@ -185,6 +185,11 @@ bool operator==(const namespace_ &left, const namespace_ &right)
     return left.namespace_path_ == right.namespace_path_;
 }
 
+bool operator<(const namespace_ &left, const namespace_ &right)
+{
+    return std::hash<namespace_>{}(left) < std::hash<namespace_>{}(right);
+}
+
 std::string namespace_::name() const
 {
     assert(size() > 0);
diff --git a/src/common/model/namespace.h b/src/common/model/namespace.h
index a6fc88a6..e8c19c82 100644
--- a/src/common/model/namespace.h
+++ b/src/common/model/namespace.h
@@ -23,9 +23,9 @@
 namespace clanguml::common::model {
 
 class namespace_ {
+public:
     using container_type = std::vector<std::string>;
 
-public:
     namespace_() = default;
 
     namespace_(const std::string &ns);
@@ -42,6 +42,7 @@ public:
     namespace_ &operator=(namespace_ &&right) noexcept = default;
 
     friend bool operator==(const namespace_ &left, const namespace_ &right);
+    friend bool operator<(const namespace_ &left, const namespace_ &right);
 
     namespace_(std::initializer_list<std::string> ns);
 
@@ -85,4 +86,23 @@ private:
     container_type namespace_path_;
 };
 
+}
+
+namespace std {
+
+template <> struct hash<clanguml::common::model::namespace_> {
+    std::size_t operator()(const clanguml::common::model::namespace_ &key) const
+    {
+        using clanguml::common::model::namespace_;
+
+        std::size_t seed = key.size();
+        for (const auto &ns : key) {
+            seed ^= std::hash<std::string>{}(ns) + 0x6a3712b5 + (seed << 6) +
+                (seed >> 2);
+        }
+
+        return seed;
+    }
+};
+
 }
\ No newline at end of file