diff --git a/llvm/include/llvm/TargetParser/Triple.h b/llvm/include/llvm/TargetParser/Triple.h
--- a/llvm/include/llvm/TargetParser/Triple.h
+++ b/llvm/include/llvm/TargetParser/Triple.h
@@ -221,7 +221,8 @@
     Emscripten,
     ShaderModel, // DirectX ShaderModel
     LiteOS,
-    LastOSType = LiteOS
+    Serenity,
+    LastOSType = Serenity
   };
   enum EnvironmentType {
     UnknownEnvironment,
@@ -668,6 +669,10 @@
     return getOS() == Triple::AIX;
   }
 
+  bool isOSSerenity() const {
+    return getOS() == Triple::Serenity;
+  }
+
   /// Tests whether the OS uses the ELF binary format.
   bool isOSBinFormatELF() const {
     return getObjectFormat() == Triple::ELF;
diff --git a/llvm/lib/TargetParser/Triple.cpp b/llvm/lib/TargetParser/Triple.cpp
--- a/llvm/lib/TargetParser/Triple.cpp
+++ b/llvm/lib/TargetParser/Triple.cpp
@@ -264,6 +264,7 @@
   case PS5: return "ps5";
   case RTEMS: return "rtems";
   case Solaris: return "solaris";
+  case Serenity: return "serenity";
   case TvOS: return "tvos";
   case UEFI: return "uefi";
   case WASI: return "wasi";
@@ -641,6 +642,7 @@
     .StartsWith("emscripten", Triple::Emscripten)
     .StartsWith("shadermodel", Triple::ShaderModel)
     .StartsWith("liteos", Triple::LiteOS)
+    .StartsWith("serenity", Triple::Serenity)
     .Default(Triple::UnknownOS);
 }
 
diff --git a/llvm/unittests/TargetParser/TripleTest.cpp b/llvm/unittests/TargetParser/TripleTest.cpp
--- a/llvm/unittests/TargetParser/TripleTest.cpp
+++ b/llvm/unittests/TargetParser/TripleTest.cpp
@@ -1003,6 +1003,18 @@
   EXPECT_EQ(Triple::LiteOS, T.getOS());
   EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
 
+  T = Triple("x86_64-pc-serenity");
+  EXPECT_EQ(Triple::x86_64, T.getArch());
+  EXPECT_EQ(Triple::PC, T.getVendor());
+  EXPECT_EQ(Triple::Serenity, T.getOS());
+  EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
+
+  T = Triple("aarch64-pc-serenity");
+  EXPECT_EQ(Triple::aarch64, T.getArch());
+  EXPECT_EQ(Triple::PC, T.getVendor());
+  EXPECT_EQ(Triple::Serenity, T.getOS());
+  EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
+
   T = Triple("huh");
   EXPECT_EQ(Triple::UnknownArch, T.getArch());
 }