diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -446,6 +446,8 @@
     switch (os) {
     case llvm::Triple::Linux:
       return new LinuxTargetInfo<SystemZTargetInfo>(Triple, Opts);
+    case llvm::Triple::ZOS:
+      return new ZOSTargetInfo<SystemZTargetInfo>(Triple, Opts);
     default:
       return new SystemZTargetInfo(Triple, Opts);
     }
diff --git a/clang/lib/Basic/Targets/OSTargets.h b/clang/lib/Basic/Targets/OSTargets.h
--- a/clang/lib/Basic/Targets/OSTargets.h
+++ b/clang/lib/Basic/Targets/OSTargets.h
@@ -721,6 +721,71 @@
   bool hasInt128Type() const override { return false; }
 };
 
+// z/OS target
+template <typename Target>
+class LLVM_LIBRARY_VISIBILITY ZOSTargetInfo : public OSTargetInfo<Target> {
+protected:
+  void getOSDefines(const LangOptions &Opts, const llvm::Triple &Triple,
+                    MacroBuilder &Builder) const override {
+    Builder.defineMacro("_LONG_LONG");
+    Builder.defineMacro("_OPEN_DEFAULT");
+    Builder.defineMacro("_UNIX03_WITHDRAWN");
+    Builder.defineMacro("__370__");
+    Builder.defineMacro("__BFP__");
+    Builder.defineMacro("__BOOL__");
+    Builder.defineMacro("__LONGNAME__");
+    Builder.defineMacro("__MVS__");
+    Builder.defineMacro("__THW_370__");
+    Builder.defineMacro("__THW_BIG_ENDIAN__");
+    Builder.defineMacro("__TOS_390__");
+    Builder.defineMacro("__TOS_MVS__");
+    Builder.defineMacro("__XPLINK__");
+
+    if (this->PointerWidth == 64) {
+      Builder.defineMacro("__64BIT__");
+    }
+
+    if (Opts.C99) {
+      Builder.defineMacro("_ISOC99_SOURCE");
+    }
+
+    if (Opts.C11 || Opts.GNUMode) {
+      Builder.defineMacro("__IBM_UTF_LITERAL");
+    }
+
+    if (Opts.C11 || (Opts.GNUMode && !Opts.CPlusPlus)) {
+      Builder.defineMacro("__IBMC_GENERIC");
+    }
+
+    if (Opts.CPlusPlus) {
+      Builder.defineMacro("__DLL__");
+      // Macro __wchar_t exposes the definition of wchar_t data type
+      // in system headers.
+      Builder.defineMacro("__wchar_t");
+      Builder.defineMacro("_XOPEN_SOURCE", "600");
+    }
+
+    if (Opts.C11 || Opts.CPlusPlus11 || Opts.GNUMode) {
+      Builder.defineMacro("__IBMC_NORETURN");
+    }
+
+    if (Opts.C11 || (Opts.GNUMode && Opts.CPlusPlus)) {
+      Builder.defineMacro("__IBM_CHAR16_T__");
+      Builder.defineMacro("__IBM_CHAR32_T__");
+      Builder.defineMacro("__IBMCPP_UTF_LITERAL__");
+    }
+
+    if (Opts.GNUMode) {
+      Builder.defineMacro("_MI_BUILTIN");
+      Builder.defineMacro("_EXT");
+    }
+  }
+
+public:
+  ZOSTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
+      : OSTargetInfo<Target>(Triple, Opts) {}
+};
+
 void addWindowsDefines(const llvm::Triple &Triple, const LangOptions &Opts,
                        MacroBuilder &Builder);
 
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -5630,6 +5630,45 @@
 // S390X:#define __s390__ 1
 // S390X:#define __s390x__ 1
 //
+// RUN: %clang_cc1 -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS %s
+// RUN: %clang_cc1 -x c -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-C %s
+// RUN: %clang_cc1 -E -dM -std=gnu99 -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS %s
+// RUN: %clang_cc1 -E -dM -std=gnu11 -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS %s
+// RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-CXX %s
+// RUN: %clang_cc1 -x c -std=c99 -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-C99 %s
+// RUN: %clang_cc1 -x c++ -std=c++11 -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-CXX %s
+// RUN: %clang_cc1 -x c++ -std=c++14 -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-CXX %s
+// RUN: %clang_cc1 -x c++ -std=gnu++11 -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-CXX -check-prefix S390X-ZOS-GXX %s
+// RUN: %clang_cc1 -x c++ -std=gnu++14 -E -dM -ffreestanding -triple=s390x-none-zos -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix S390X-ZOS -check-prefix S390X-ZOS-CXX -check-prefix S390X-ZOS-GXX %s
+//
+// S390X-ZOS-GXX:#define _EXT 1
+// S390X-ZOS-C99:#define _ISOC99_SOURCE 1
+// S390X-ZOS:#define _LONG_LONG 1
+// S390X-ZOS-GXX:#define _MI_BUILTIN 1
+// S390X-ZOS:#define _OPEN_DEFAULT 1
+// S390X-ZOS:#define _UNIX03_WITHDRAWN 1
+// S390X-ZOS-CXX:#define _XOPEN_SOURCE 600
+// S390X-ZOS:#define __370__ 1
+// S390X-ZOS:#define __64BIT__ 1
+// S390X-ZOS:#define __BFP__ 1
+// S390X-ZOS:#define __BOOL__ 1
+// S390X-ZOS-CXX:#define __DLL__ 1
+// S390X-ZOS-C:#define __IBMC_GENERIC 1
+// S390X-ZOS-C:#define __IBMC_NORETURN 1
+// S390X-ZOS-C:#define __IBM_UTF_LITERAL 1
+// S390X-ZOS-GXX:#define __IBMCPP_UTF_LITERAL__ 1
+// S390X-ZOS-GXX:#define __IBMC_NORETURN 1
+// S390X-ZOS-GXX:#define __IBM_CHAR16_T__ 1
+// S390X-ZOS-GXX:#define __IBM_CHAR32_T__ 1
+// S390X-ZOS:#define __LONGNAME__ 1
+// S390X-ZOS:#define __MVS__ 1
+// S390X-ZOS:#define __THW_370__ 1
+// S390X-ZOS:#define __THW_BIG_ENDIAN__ 1
+// S390X-ZOS:#define __TOS_390__ 1
+// S390X-ZOS:#define __TOS_MVS__ 1
+// S390X-ZOS:#define __XPLINK__ 1
+// S390X-ZOS-CXX:#define __wchar_t 1
+//
 // RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=sparc-none-none < /dev/null | FileCheck -match-full-lines -check-prefix SPARC -check-prefix SPARC-DEFAULT %s
 // RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=sparc-rtems-elf < /dev/null | FileCheck -match-full-lines -check-prefix SPARC -check-prefix SPARC-DEFAULT %s
 // RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=sparc-none-netbsd < /dev/null | FileCheck -match-full-lines -check-prefix SPARC -check-prefix SPARC-NETOPENBSD %s