Index: include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- include/clang/ASTMatchers/ASTMatchers.h
+++ include/clang/ASTMatchers/ASTMatchers.h
@@ -714,6 +714,18 @@
 ///   matches \code using X::x \endcode
 const internal::VariadicDynCastAllOfMatcher<Decl, UsingDecl> usingDecl;
 
+/// \brief Matches using namespace declarations.
+///
+/// Given
+/// \code
+///   namespace X { int x; }
+///   using namespace X;
+/// \endcode
+/// usingDirectiveDecl()
+///   matches \code using namespace X \endcode
+const internal::VariadicDynCastAllOfMatcher<Decl, UsingDirectiveDecl>
+    usingDirectiveDecl;
+
 /// \brief Matches unresolved using value declarations.
 ///
 /// Given
Index: unittests/ASTMatchers/ASTMatchersTest.cpp
===================================================================
--- unittests/ASTMatchers/ASTMatchersTest.cpp
+++ unittests/ASTMatchers/ASTMatchersTest.cpp
@@ -3038,6 +3038,13 @@
       declRefExpr(throughUsingDecl(anything()))));
 }
 
+TEST(UsingDirectiveDeclaration, MatchesUsingNamespace) {
+  EXPECT_TRUE(matches("namespace X { int x; } using namespace X;",
+                      usingDirectiveDecl()));
+  EXPECT_FALSE(
+      matches("namespace X { int x; } using X::x;", usingDirectiveDecl()));
+}
+
 TEST(SingleDecl, IsSingleDecl) {
   StatementMatcher SingleDeclStmt =
       declStmt(hasSingleDecl(varDecl(hasInitializer(anything()))));