diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5934,7 +5934,7 @@
   HelpText<"Set runtime encoding, supports only UTF-8">,
   Alias<fexec_charset_EQ>;
 def _SLASH_std : CLCompileJoined<"std:">,
-  HelpText<"Set language version (c++14,c++17,c++latest,c11,c17)">;
+  HelpText<"Set language version (c++14,c++17,c++20,c++latest,c11,c17)">;
 def _SLASH_U : CLJoinedOrSeparate<"U">, HelpText<"Undefine macro">,
   MetaVarName<"<macro>">, Alias<U>;
 def _SLASH_validate_charset : CLFlag<"validate-charset">,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6080,7 +6080,8 @@
       LanguageStandard = llvm::StringSwitch<StringRef>(StdArg->getValue())
                              .Case("c++14", "-std=c++14")
                              .Case("c++17", "-std=c++17")
-                             .Case("c++latest", "-std=c++20")
+                             .Case("c++20", "-std=c++20")
+                             .Case("c++latest", "-std=c++2b")
                              .Default("");
       if (LanguageStandard.empty())
         D.Diag(clang::diag::warn_drv_unused_argument)
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -594,8 +594,11 @@
 // RUN: %clang_cl -fmsc-version=1900 -TP -std:c++17 -### -- %s 2>&1 | FileCheck -check-prefix=STDCXX17 %s
 // STDCXX17: -std=c++17
 
+// RUN: %clang_cl -fmsc-version=1900 -TP -std:c++20 -### -- %s 2>&1 | FileCheck -check-prefix=STDCXX20 %s
+// STDCXX20: -std=c++20
+
 // RUN: %clang_cl -fmsc-version=1900 -TP -std:c++latest -### -- %s 2>&1 | FileCheck -check-prefix=STDCXXLATEST %s
-// STDCXXLATEST: -std=c++20
+// STDCXXLATEST: -std=c++2b
 
 // RUN: env CL="/Gy" %clang_cl -### -- %s 2>&1 | FileCheck -check-prefix=ENV-CL %s
 // ENV-CL: "-ffunction-sections"