diff --git a/Misc/NEWS.d/next/Build/2026-09-07-00-30-00.gh-issue-156895.Jakqud.rst b/Misc/NEWS.d/next/Build/2026-09-07-00-30-00.gh-issue-156895.Jakqud.rst
new file mode 100644
index 000000000000000..a7167c02d3ba435
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2026-09-07-00-30-00.gh-issue-156895.Jakqud.rst
@@ -0,0 +1 @@
+Document the ``CXX`` environment variable in the :program:`configure` ``--help`` output.
diff --git a/configure b/configure
index 7e4844263a3491c..a57fefbe0258761 100755
--- a/configure
+++ b/configure
@@ -1175,6 +1175,7 @@ LDFLAGS
 LIBS
 CPPFLAGS
 CPP
+CXX
 PROFILE_TASK
 BOLT_COMMON_FLAGS
 BOLT_INSTRUMENT_FLAGS
@@ -2030,6 +2031,7 @@ Some influential environment variables:
   CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
               you have headers in a nonstandard directory <include dir>
   CPP         C preprocessor
+  CXX         C++ compiler command
   PROFILE_TASK
               Python args for PGO generation task
   BOLT_COMMON_FLAGS
diff --git a/configure.ac b/configure.ac
index 8345c97349b7382..6e1f99436fd6bfb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1148,7 +1148,7 @@ AC_CACHE_CHECK([for GCC compatible compiler],
                [ac_cv_gcc_compat=yes],
                [ac_cv_gcc_compat=no])])
 
-AC_SUBST([CXX])
+AC_ARG_VAR([CXX], [C++ compiler command])
 
 preset_cxx="$CXX"
 if test -z "$CXX"