diff --git a/include/__functional_03 b/include/__functional_03
index f9a3d976..25826017 100644
--- a/include/__functional_03
+++ b/include/__functional_03
@@ -33,28 +33,28 @@ public:
     // invoke
 
     typename __invoke_return<type>::type
-       operator() ()
+       operator() () const
        {
            return __invoke(__f_);
        }
 
     template <class _A0>
        typename __invoke_return0<type, _A0>::type
-          operator() (_A0& __a0)
+          operator() (_A0& __a0) const
           {
               return __invoke(__f_, __a0);
           }
 
     template <class _A0, class _A1>
        typename __invoke_return1<type, _A0, _A1>::type
-          operator() (_A0& __a0, _A1& __a1)
+          operator() (_A0& __a0, _A1& __a1) const
           {
               return __invoke(__f_, __a0, __a1);
           }
 
     template <class _A0, class _A1, class _A2>
        typename __invoke_return2<type, _A0, _A1, _A2>::type
-          operator() (_A0& __a0, _A1& __a1, _A2& __a2)
+          operator() (_A0& __a0, _A1& __a1, _A2& __a2) const
           {
               return __invoke(__f_, __a0, __a1, __a2);
           }
diff --git a/include/functional b/include/functional
index d40f70af..891ed460 100644
--- a/include/functional
+++ b/include/functional
@@ -1221,7 +1221,7 @@ public:
     template <class... _ArgTypes>
        _LIBCPP_INLINE_VISIBILITY
        typename __invoke_return<type, _ArgTypes...>::type
-          operator() (_ArgTypes&&... __args)
+          operator() (_ArgTypes&&... __args) const
           {
               return __invoke(__f_, _VSTD::forward<_ArgTypes>(__args)...);
           }
diff --git a/test/utilities/function.objects/func.memfn/member_data.pass.cpp b/test/utilities/function.objects/func.memfn/member_data.pass.cpp
index 048fca4d..dff211c6 100644
--- a/test/utilities/function.objects/func.memfn/member_data.pass.cpp
+++ b/test/utilities/function.objects/func.memfn/member_data.pass.cpp
@@ -32,6 +32,8 @@ test(F f)
     assert(a.data_ == 6);
     const A* cap = ap;
     assert(f(cap) == f(ap));
+    const F& cf = f;
+    assert(cf(ap) == f(ap));
     }
 }
 
diff --git a/test/utilities/function.objects/func.memfn/member_function.pass.cpp b/test/utilities/function.objects/func.memfn/member_function.pass.cpp
index 01a5f8e5..4096bd81 100644
--- a/test/utilities/function.objects/func.memfn/member_function.pass.cpp
+++ b/test/utilities/function.objects/func.memfn/member_function.pass.cpp
@@ -31,6 +31,8 @@ test0(F f)
     assert(f(a) == 'a');
     A* ap = &a;
     assert(f(ap) == 'a');
+    const F& cf = f;
+    assert(cf(ap) == 'a');
     }
 }
 
@@ -43,6 +45,8 @@ test1(F f)
     assert(f(a, 1) == 'b');
     A* ap = &a;
     assert(f(ap, 2) == 'b');
+    const F& cf = f;
+    assert(cf(ap, 2) == 'b');
     }
 }
 
@@ -55,6 +59,8 @@ test2(F f)
     assert(f(a, 1, 2) == 'c');
     A* ap = &a;
     assert(f(ap, 2, 3.5) == 'c');
+    const F& cf = f;
+    assert(cf(ap, 2, 3.5) == 'c');
     }
 }
 
diff --git a/test/utilities/function.objects/func.memfn/member_function_const.pass.cpp b/test/utilities/function.objects/func.memfn/member_function_const.pass.cpp
index 978f9f09..be22443e 100644
--- a/test/utilities/function.objects/func.memfn/member_function_const.pass.cpp
+++ b/test/utilities/function.objects/func.memfn/member_function_const.pass.cpp
@@ -33,6 +33,8 @@ test0(F f)
     assert(f(ap) == 'a');
     const A* cap = &a;
     assert(f(cap) == 'a');
+    const F& cf = f;
+    assert(cf(ap) == 'a');
     }
 }
 
@@ -47,6 +49,8 @@ test1(F f)
     assert(f(ap, 2) == 'b');
     const A* cap = &a;
     assert(f(cap, 2) == 'b');
+    const F& cf = f;
+    assert(cf(ap, 2) == 'b');
     }
 }
 
@@ -61,6 +65,8 @@ test2(F f)
     assert(f(ap, 2, 3.5) == 'c');
     const A* cap = &a;
     assert(f(cap, 2, 3.5) == 'c');
+    const F& cf = f;
+    assert(cf(ap, 2, 3.5) == 'c');
     }
 }
 
diff --git a/test/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp b/test/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
index 1e00b4d6..329ac16a 100644
--- a/test/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
+++ b/test/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
@@ -33,6 +33,8 @@ test0(F f)
     assert(f(ap) == 'a');
     const volatile A* cap = &a;
     assert(f(cap) == 'a');
+    const F& cf = f;
+    assert(cf(ap) == 'a');
     }
 }
 
@@ -47,6 +49,8 @@ test1(F f)
     assert(f(ap, 2) == 'b');
     const volatile A* cap = &a;
     assert(f(cap, 2) == 'b');
+    const F& cf = f;
+    assert(cf(ap, 2) == 'b');
     }
 }
 
@@ -61,6 +65,8 @@ test2(F f)
     assert(f(ap, 2, 3.5) == 'c');
     const volatile A* cap = &a;
     assert(f(cap, 2, 3.5) == 'c');
+    const F& cf = f;
+    assert(cf(ap, 2, 3.5) == 'c');
     }
 }
 
diff --git a/test/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp b/test/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
index 4d0654a9..743ded99 100644
--- a/test/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
+++ b/test/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
@@ -33,6 +33,8 @@ test0(F f)
     assert(f(ap) == 'a');
     volatile A* cap = &a;
     assert(f(cap) == 'a');
+    const F& cf = f;
+    assert(cf(ap) == 'a');
     }
 }
 
@@ -47,6 +49,8 @@ test1(F f)
     assert(f(ap, 2) == 'b');
     volatile A* cap = &a;
     assert(f(cap, 2) == 'b');
+    const F& cf = f;
+    assert(cf(ap, 2) == 'b');
     }
 }
 
@@ -61,6 +65,8 @@ test2(F f)
     assert(f(ap, 2, 3.5) == 'c');
     volatile A* cap = &a;
     assert(f(cap, 2, 3.5) == 'c');
+    const F& cf = f;
+    assert(cf(ap, 2, 3.5) == 'c');
     }
 }