diff --git a/clang/lib/Driver/ToolChains/AIX.h b/clang/lib/Driver/ToolChains/AIX.h
--- a/clang/lib/Driver/ToolChains/AIX.h
+++ b/clang/lib/Driver/ToolChains/AIX.h
@@ -63,9 +63,16 @@
   bool isPIEDefault() const override { return false; }
   bool isPICDefaultForced() const override { return true; }
 
+  void
+  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
+                            llvm::opt::ArgStringList &CC1Args) const override;
+
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
+
+private:
+  llvm::StringRef GetHeaderSysroot(const llvm::opt::ArgList &DriverArgs) const;
 };
 
 } // end namespace toolchains
diff --git a/clang/lib/Driver/ToolChains/AIX.cpp b/clang/lib/Driver/ToolChains/AIX.cpp
--- a/clang/lib/Driver/ToolChains/AIX.cpp
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -13,12 +13,15 @@
 #include "clang/Driver/Options.h"
 #include "clang/Driver/SanitizerArgs.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/Path.h"
 
 using AIX = clang::driver::toolchains::AIX;
 using namespace clang::driver;
 using namespace clang::driver::tools;
+using namespace clang::driver::toolchains;
 
 using namespace llvm::opt;
+using namespace llvm::sys;
 
 void aix::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                   const InputInfo &Output,
@@ -163,6 +166,43 @@
   getFilePaths().push_back(getDriver().SysRoot + "/usr/lib");
 }
 
+// Returns the effective header sysroot path to use.
+// This comes from either -isysroot or --sysroot.
+llvm::StringRef
+AIX::GetHeaderSysroot(const llvm::opt::ArgList &DriverArgs) const {
+  if (DriverArgs.hasArg(options::OPT_isysroot))
+    return DriverArgs.getLastArgValue(options::OPT_isysroot);
+  if (!getDriver().SysRoot.empty())
+    return getDriver().SysRoot;
+  return "/";
+}
+
+void AIX::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                    ArgStringList &CC1Args) const {
+  // Return if -nostdinc is specified as a driver option.
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
+    return;
+
+  llvm::StringRef Sysroot = GetHeaderSysroot(DriverArgs);
+  const Driver &D = getDriver();
+
+  // Add the Clang builtin headers (<resource>/include).
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    SmallString<128> P(D.ResourceDir);
+    path::append(P, "/include");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  }
+
+  // Return if -nostdlibinc is specified as a driver option.
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+  // Add <sysroot>/usr/include.
+  SmallString<128> UP(Sysroot);
+  path::append(UP, "/usr/include");
+  addSystemInclude(DriverArgs, CC1Args, UP.str());
+}
+
 auto AIX::buildAssembler() const -> Tool * { return new aix::Assembler(*this); }
 
 auto AIX::buildLinker() const -> Tool * { return new aix::Linker(*this); }
diff --git a/clang/lib/Frontend/InitHeaderSearch.cpp b/clang/lib/Frontend/InitHeaderSearch.cpp
--- a/clang/lib/Frontend/InitHeaderSearch.cpp
+++ b/clang/lib/Frontend/InitHeaderSearch.cpp
@@ -381,6 +381,7 @@
   case llvm::Triple::Linux:
   case llvm::Triple::Hurd:
   case llvm::Triple::Solaris:
+  case llvm::Triple::AIX:
     llvm_unreachable("Include management is handled in the driver.");
     break;
   case llvm::Triple::Win32:
@@ -424,6 +425,7 @@
   case llvm::Triple::Hurd:
   case llvm::Triple::Solaris:
   case llvm::Triple::WASI:
+  case llvm::Triple::AIX:
     return;
 
   case llvm::Triple::Win32:
diff --git a/clang/test/Driver/aix-toolchain-include.cpp b/clang/test/Driver/aix-toolchain-include.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/aix-toolchain-include.cpp
@@ -0,0 +1,136 @@
+// Tests that the AIX toolchain adds system includes to its search path.
+
+// Check powerpc-ibm-aix, 32-bit/64-bit.
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:   | FileCheck -check-prefix=CHECK-INTERNAL-INCLUDE %s
+
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:   | FileCheck -check-prefix=CHECK-INTERNAL-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:   | FileCheck -check-prefix=CHECK-INTERNAL-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:   | FileCheck -check-prefix=CHECK-INTERNAL-INCLUDE %s
+
+// CHECK-INTERNAL-INCLUDE:	{{.*}}clang{{.*}}" "-cc1"
+// CHECK-INTERNAL-INCLUDE:	"-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-INTERNAL-INCLUDE:	"-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-INTERNAL-INCLUDE:	"-internal-isystem" "[[RESOURCE_DIR]]{{(/|\\\\)}}include"
+// CHECK-INTERNAL-INCLUDE:	"-internal-isystem" "[[SYSROOT]]/usr/include"
+
+// Check powerpc-ibm-aix, 32-bit/64-bit. -nostdinc option.
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDINC-INCLUDE %s
+
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDINC-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDINC-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDINC-INCLUDE %s
+
+// CHECK-NOSTDINC-INCLUDE:	{{.*}}clang{{.*}}" "-cc1"
+// CHECK-NOSTDINC-INCLUDE:	"-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-NOSTDINC-INCLUDE:	"-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-NOSTDINC-INCLUDE-NOT:	"-internal-isystem"
+
+// Check powerpc-ibm-aix, 32-bit/64-bit. -nostdlibinc option.
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdlibinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDLIBINC-INCLUDE %s
+
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdlibinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDLIBINC-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdlibinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDLIBINC-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nostdlibinc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOSTDLIBINC-INCLUDE %s
+
+// CHECK-NOSTDLIBINC-INCLUDE:	{{.*}}clang{{.*}}" "-cc1"
+// CHECK-NOSTDLIBINC-INCLUDE:	"-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-NOSTDLIBINC-INCLUDE:	"-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-NOSTDLIBINC-INCLUDE:	"-internal-isystem" "[[RESOURCE_DIR]]{{(/|\\\\)}}include"
+// CHECK-NOSTDLIBINC-INCLUDE-NOT:	"-internal-isystem" "[[SYSROOT]]/usr/include"
+
+// Check powerpc-ibm-aix, 32-bit/64-bit. -nobuiltininc option.
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nobuiltininc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOBUILTININC-INCLUDE %s
+
+// RUN: %clangxx -### -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nobuiltininc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOBUILTININC-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nobuiltininc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOBUILTININC-INCLUDE %s
+
+// RUN: %clang -### -xc -no-canonical-prefixes %s 2>&1 \
+// RUN:		-target powerpc64-ibm-aix \
+// RUN:		-resource-dir=%S/Inputs/resource_dir \
+// RUN:		--sysroot=%S/Inputs/basic_aix_tree \
+// RUN:		-nobuiltininc \
+// RUN:   | FileCheck -check-prefix=CHECK-NOBUILTININC-INCLUDE %s
+
+// CHECK-NOBUILTININC-INCLUDE:	{{.*}}clang{{.*}}" "-cc1"
+// CHECK-NOBUILTININC-INCLUDE:	"-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-NOBUILTININC-INCLUDE:	"-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-NOBUILTININC-INCLUDE-NOT:	"-internal-isystem" "[[RESOURCE_DIR]]{{(/|\\\\)}}include"
+// CHECK-NOBUILTININC-INCLUDE:	"-internal-isystem" "[[SYSROOT]]/usr/include"