diff --git a/test/strings/string.conversions/stol.pass.cpp b/test/strings/string.conversions/stol.pass.cpp
index 0338ef18..d1cd75dc 100644
--- a/test/strings/string.conversions/stol.pass.cpp
+++ b/test/strings/string.conversions/stol.pass.cpp
@@ -6,6 +6,9 @@
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// XFAIL: with_system_lib=x86_64-apple-darwin11
+// XFAIL: with_system_lib=x86_64-apple-darwin12
 
 // <string>
 
diff --git a/test/strings/string.conversions/stoul.pass.cpp b/test/strings/string.conversions/stoul.pass.cpp
index dd42b7e9..fcd19e88 100644
--- a/test/strings/string.conversions/stoul.pass.cpp
+++ b/test/strings/string.conversions/stoul.pass.cpp
@@ -6,6 +6,9 @@
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// XFAIL: with_system_lib=x86_64-apple-darwin11
+// XFAIL: with_system_lib=x86_64-apple-darwin12
 
 // <string>
 
diff --git a/test/strings/string.conversions/stoull.pass.cpp b/test/strings/string.conversions/stoull.pass.cpp
index 19df7065..b1a2f9f0 100644
--- a/test/strings/string.conversions/stoull.pass.cpp
+++ b/test/strings/string.conversions/stoull.pass.cpp
@@ -6,6 +6,9 @@
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// XFAIL: with_system_lib=x86_64-apple-darwin11
+// XFAIL: with_system_lib=x86_64-apple-darwin12
 
 // <string>