diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index a65c78f7240..f562cdebf4c 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -738,7 +738,9 @@ enum cxx_dialect {
   /* C++17 */
   cxx17,
   /* C++20 */
-  cxx20
+  cxx20,
+  /* C++2b (C++23?) */
+  cxx2b
 };

 /* The C++ dialect being used. C++98 is the default.  */
diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index 3cdf41bc6e2..15f120d475d 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -113,6 +113,7 @@ static void set_std_cxx11 (int);
 static void set_std_cxx14 (int);
 static void set_std_cxx17 (int);
 static void set_std_cxx20 (int);
+static void set_std_cxx2b (int);
 static void set_std_c89 (int, int);
 static void set_std_c99 (int);
 static void set_std_c11 (int);
@@ -649,6 +650,12 @@ c_common_handle_option (size_t scode, const char
*arg, HOST_WIDE_INT value,
     set_std_cxx20 (code == OPT_std_c__20 /* ISO */);
       break;

+    case OPT_std_c__2b:
+    case OPT_std_gnu__2b:
+      if (!preprocessing_asm_p)
+    set_std_cxx2b (code == OPT_std_c__2b /* ISO */);
+      break;
+
     case OPT_std_c90:
     case OPT_std_iso9899_199409:
       if (!preprocessing_asm_p)
@@ -1019,7 +1026,7 @@ c_common_post_options (const char **pfilename)
     warn_narrowing = 1;

       /* Unless -f{,no-}ext-numeric-literals has been used explicitly,
-     for -std=c++{11,14,17,2a} default to -fno-ext-numeric-literals.  */
+     for -std=c++{11,14,17,20,2b} default to -fno-ext-numeric-literals.  */
       if (flag_iso && !global_options_set.x_flag_ext_numeric_literals)
     cpp_opts->ext_numeric_literals = 0;
     }
@@ -1763,7 +1770,7 @@ set_std_cxx20 (int iso)
   flag_no_gnu_keywords = iso;
   flag_no_nonansi_builtin = iso;
   flag_iso = iso;
-  /* C++17 includes the C11 standard library.  */
+  /* C++20 includes the C11 standard library.  */
   flag_isoc94 = 1;
   flag_isoc99 = 1;
   flag_isoc11 = 1;
@@ -1773,6 +1780,24 @@ set_std_cxx20 (int iso)
   lang_hooks.name = "GNU C++20";
 }

+/* Set the C++ 202b standard (without GNU extensions if ISO).  */
+static void
+set_std_cxx2b (int iso)
+{
+  cpp_set_lang (parse_in, iso ? CLK_CXX2B: CLK_GNUCXX2B);
+  flag_no_gnu_keywords = iso;
+  flag_no_nonansi_builtin = iso;
+  flag_iso = iso;
+  /* C++2b includes the C11 standard library.  */
+  flag_isoc94 = 1;
+  flag_isoc99 = 1;
+  flag_isoc11 = 1;
+  /* C++2b includes coroutines.  */
+  flag_coroutines = true;
+  cxx_dialect = cxx2b;
+  lang_hooks.name = "GNU C++20"; /* Pretend C++20 until standardization.  */
+}
+
 /* Args to -d specify what to dump.  Silently ignore
    unrecognized options; they may be aimed at toplev.c.  */
 static void
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 1766364806e..273772a0cd5 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -2214,6 +2214,10 @@ std=c++20
 C++ ObjC++
 Conform to the ISO 2020 C++ draft standard (experimental and
incomplete support).

+std=c++2b
+C++ ObjC++
+Conform to the ISO 2023(?) C++ draft standard (experimental and
incomplete support).
+
 std=c11
 C ObjC
 Conform to the ISO 2011 C standard.
@@ -2292,6 +2296,10 @@ std=gnu++20
 C++ ObjC++
 Conform to the ISO 2020 C++ draft standard with GNU extensions
(experimental and incomplete support).

+std=gnu++2b
+C++ ObjC++
+Conform to the ISO 2023(?) C++ draft standard with GNU extensions
(experimental and incomplete support).
+
 std=gnu11
 C ObjC
 Conform to the ISO 2011 C standard with GNU extensions.
diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index 25f2625d8bd..f801024affd 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -1907,9 +1907,10 @@ selected, the value of the macro is
 @code{201103L} for the 2011 C++ standard,
 @code{201402L} for the 2014 C++ standard,
 @code{201703L} for the 2017 C++ standard,
-or an unspecified value strictly larger than @code{201703L} for the
-experimental languages enabled by @option{-std=c++2a} and
-@option{-std=gnu++2a}.
+@code{202002L} for the 2020 C++ standard,
+or an unspecified value strictly larger than @code{202002L} for the
+experimental languages enabled by @option{-std=c++2b} and
+@option{-std=gnu++2b}.

 @item __OBJC__
 This macro is defined, with value 1, when the Objective-C compiler is in
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 226b8ade430..11a6e9a23c3 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2430,6 +2430,16 @@ GNU dialect of @option{-std=c++20}.
 Support is experimental, and could change in incompatible ways in
 future releases.
 The name @samp{gnu++2a} is deprecated.
+
+@item c++2b
+The next revision of the ISO C++ standard, planned for
+2023.  Support is highly experimental, and will almost certainly
+change in incompatible ways in future releases.
+
+@item gnu++2b
+GNU dialect of @option{-std=c++2b}.  Support is highly experimental,
+and will almost certainly change in incompatible ways in future
+releases.
 @end table

 @item -fgnu89-inline
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 8b6890a5097..97df6604373 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -24445,6 +24445,10 @@ static char *producer_string;
 static const char *
 highest_c_language (const char *lang1, const char *lang2)
 {
+  if (strcmp ("GNU C++23", lang1) == 0 || strcmp ("GNU C++23", lang2) == 0)
+    return "GNU C++23";
+  if (strcmp ("GNU C++20", lang1) == 0 || strcmp ("GNU C++20", lang2) == 0)
+    return "GNU C++20";
   if (strcmp ("GNU C++17", lang1) == 0 || strcmp ("GNU C++17", lang2) == 0)
     return "GNU C++17";
   if (strcmp ("GNU C++14", lang1) == 0 || strcmp ("GNU C++14", lang2) == 0)
@@ -24550,7 +24554,8 @@ gen_compile_unit_die (const char *filename)
       else if (strcmp (language_string, "GNU C++14") == 0)
         language = DW_LANG_C_plus_plus_14;
       else if (strcmp (language_string, "GNU C++17") == 0
-           || strcmp (language_string, "GNU C++20") == 0)
+           || strcmp (language_string, "GNU C++20") == 0
+           || strcmp (language_string, "GNU C++23") == 0)
         /* For now.  */
         language = DW_LANG_C_plus_plus_14;
     }
diff --git a/gcc/testsuite/g++.dg/cpp2b/cplusplus.C
b/gcc/testsuite/g++.dg/cpp2b/cplusplus.C
new file mode 100644
index 00000000000..615d9f081de
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2b/cplusplus.C
@@ -0,0 +1,4 @@
+// { dg-do compile }
+// { dg-options "-std=c++2b" }
+
+static_assert(__cplusplus > 202002L);
diff --git a/gcc/testsuite/lib/target-supports.exp
b/gcc/testsuite/lib/target-supports.exp
index 5cf0f4218a6..31be4de12a5 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -9434,7 +9434,6 @@ proc check_effective_target_c++14_only { } {
     }
     return 0
 }
-
 proc check_effective_target_c++14 { } {
     if [check_effective_target_c++14_only] {
     return 1
@@ -9475,7 +9474,6 @@ proc check_effective_target_c++17_only { } {
     }
     return 0
 }
-
 proc check_effective_target_c++17 { } {
     if [check_effective_target_c++17_only] {
     return 1
@@ -9489,12 +9487,12 @@ proc check_effective_target_c++17_down { } {
     return [expr ![check_effective_target_c++2a] ]
 }

-proc check_effective_target_c++2a_only { } {
+proc check_effective_target_c++20_only { } {
     global cxx_default
     if ![check_effective_target_c++] {
     return 0
     }
-    if [check-flags { { } { } { -std=c++2a -std=gnu++2a -std=c++20
-std=gnu++20 } }] {
+    if [check-flags { { } { } { -std=c++20 -std=gnu++20 -std=c++2a
-std=gnu++2a } }] {
     return 1
     }
     if { $cxx_default == "c++20" && [check-flags { { } { } { } {
-std=* } }] } {
@@ -9502,18 +9500,37 @@ proc check_effective_target_c++2a_only { } {
     }
     return 0
 }
-proc check_effective_target_c++2a { } {
-    return [check_effective_target_c++2a_only]
+proc check_effective_target_c++20 { } {
+    if [check_effective_target_c++20_only] {
+    return 1
+    }
+    return [check_effective_target_c++2b]
 }
-
-proc check_effective_target_c++20_only { } {
-    return [check_effective_target_c++2a_only]
+proc check_effective_target_c++20_down { } {
+    if ![check_effective_target_c++] {
+    return 0
+    }
+    return [expr ![check_effective_target_c++20] ]
 }

-proc check_effective_target_c++20 { } {
-    return [check_effective_target_c++2a]
+proc check_effective_target_c++2b_only { } {
+    global cxx_default
+    if ![check_effective_target_c++] {
+    return 0
+    }
+    if [check-flags { { } { } { -std=c++2b -std=gnu++2b } }] {
+    return 1
+    }
+    if { $cxx_default == "c++23" && [check-flags { { } { } { } {
-std=* } }] } {
+    return 1
+    }
+    return 0
+}
+proc check_effective_target_c++2b { } {
+    return [check_effective_target_c++2b_only]
 }

+
 # Check for C++ Concepts support, i.e. -fconcepts flag.
 proc check_effective_target_concepts { } {
     if [check_effective_target_c++2a] {
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index bcc50ba45f6..c213fbac0b1 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -173,7 +173,8 @@ enum c_lang {CLK_GNUC89 = 0, CLK_GNUC99,
CLK_GNUC11, CLK_GNUC17, CLK_GNUC2X,
          CLK_STDC2X,
          CLK_GNUCXX, CLK_CXX98, CLK_GNUCXX11, CLK_CXX11,
          CLK_GNUCXX14, CLK_CXX14, CLK_GNUCXX17, CLK_CXX17,
-         CLK_GNUCXX20, CLK_CXX20, CLK_ASM};
+         CLK_GNUCXX20, CLK_CXX20, CLK_GNUCXX2B, CLK_CXX2B,
+         CLK_ASM};

 /* Payload of a NUMBER, STRING, CHAR or COMMENT token.  */
 struct GTY(()) cpp_string {
diff --git a/libcpp/init.c b/libcpp/init.c
index a5103c4d454..80543f90a51 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -119,6 +119,8 @@ static const struct lang_flags lang_defaults[] =
   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,
  1,     0,   1,      0,   1,     0 },
   /* GNUCXX20 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,
  1,     0,   1,      1,   1,     0 },
   /* CXX20    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,
  1,     0,   1,      1,   1,     0 },
+  /* GNUCXX2B */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,
  1,     0,   1,      1,   1,     0 },
