diff --git a/lldb/unittests/ObjectFile/MachO/TestObjectFileMachO.cpp b/lldb/unittests/ObjectFile/MachO/TestObjectFileMachO.cpp
index 0ef2d0b85fd36..71ff866abb352 100644
--- a/lldb/unittests/ObjectFile/MachO/TestObjectFileMachO.cpp
+++ b/lldb/unittests/ObjectFile/MachO/TestObjectFileMachO.cpp
@@ -94,4 +94,59 @@ TEST_F(ObjectFileMachOTest, IndirectSymbolsInTheSharedCache) {
   for (size_t i = 0; i < 10; i++)
     OF->ParseSymtab(symtab);
 }
+
+TEST_F(ObjectFileMachOTest, ObjectFormatWithoutVersionLoadCommand) {
+  // A Mach-O file without the load command LC_BUILD_VERSION.
+  const char *yamldata = R"(
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x0100000C
+  cpusubtype:      0x00000000
+  filetype:        0x00000001
+  ncmds:           1
+  sizeofcmds:      152
+  flags:           0x00002000
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         152
+    segname:         __TEXT
+    vmaddr:          0
+    vmsize:          4
+    fileoff:         184
+    filesize:        4
+    maxprot:         7
+    initprot:        7
+    nsects:          1
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x0000000000000000
+        content:         'AABBCCDD'
+        size:            4
+        offset:          184
+        align:           0
+        reloff:          0x00000000
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+...
+)";
+
+  // Perform setup.
+  llvm::Expected<TestFile> file = TestFile::fromYaml(yamldata);
+  EXPECT_THAT_EXPECTED(file, llvm::Succeeded());
+  auto module_sp = std::make_shared<Module>(file->moduleSpec());
+  ASSERT_NE(module_sp, nullptr);
+  auto object_file = module_sp->GetObjectFile();
+  ASSERT_NE(object_file, nullptr);
+
+  // Verify that the object file is recognized as Mach-O.
+  ASSERT_EQ(object_file->GetArchitecture().GetTriple().getObjectFormat(),
+            llvm::Triple::MachO);
+}
 #endif
diff --git a/llvm/lib/TargetParser/Triple.cpp b/llvm/lib/TargetParser/Triple.cpp
index 6a559ff023caa..81b023406a3e3 100644
--- a/llvm/lib/TargetParser/Triple.cpp
+++ b/llvm/lib/TargetParser/Triple.cpp
@@ -933,6 +933,8 @@ static Triple::ObjectFormatType getDefaultFormat(const Triple &T) {
     case Triple::Win32:
     case Triple::UEFI:
       return Triple::COFF;
+    case Triple::UnknownOS:
+      return T.getVendor() == Triple::Apple ? Triple::MachO : Triple::ELF;
     default:
       return T.isOSDarwin() ? Triple::MachO : Triple::ELF;
     }
diff --git a/llvm/unittests/TargetParser/TripleTest.cpp b/llvm/unittests/TargetParser/TripleTest.cpp
index bbd12e6d0e412..ce71a80b40f2a 100644
--- a/llvm/unittests/TargetParser/TripleTest.cpp
+++ b/llvm/unittests/TargetParser/TripleTest.cpp
@@ -2579,6 +2579,13 @@ TEST(TripleTest, FileFormat) {
   EXPECT_EQ(Triple::SPIRV, Triple("spirv32-apple-macosx").getObjectFormat());
   EXPECT_EQ(Triple::SPIRV, Triple("spirv64-apple-macosx").getObjectFormat());
   EXPECT_EQ(Triple::DXContainer, Triple("dxil-apple-macosx").getObjectFormat());
+
+  EXPECT_EQ(Triple::MachO, Triple("aarch64-apple-macosx").getObjectFormat());
+  EXPECT_EQ(Triple::MachO, Triple("x86_64-apple-macosx").getObjectFormat());
+  EXPECT_EQ(Triple::MachO, Triple("aarch64-apple").getObjectFormat());
+  EXPECT_EQ(Triple::MachO, Triple("x86_64-apple").getObjectFormat());
+  EXPECT_EQ(Triple::ELF, Triple("aarch64").getObjectFormat());
+  EXPECT_EQ(Triple::ELF, Triple("x86_64").getObjectFormat());
 }
 
 TEST(TripleTest, NormalizeWindows) {