diff --git a/Misc/NEWS.d/next/Build/2026-07-19-12-16-31.gh-issue-154070.f5da07.rst b/Misc/NEWS.d/next/Build/2026-07-19-12-16-31.gh-issue-154070.f5da07.rst
new file mode 100644
index 000000000000000..31c6fd3ece35322
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2026-07-19-12-16-31.gh-issue-154070.f5da07.rst
@@ -0,0 +1,4 @@
+Build the :mod:`curses` module against a wide-character capable ncurses
+even when it is not named ``ncursesw`` -- for example the pkgsrc ncurses on
+NetBSD and illumos, or the system ncurses on macOS.  Such a library
+previously produced a narrow build.
diff --git a/configure b/configure
index dd506e6899515b2..51259e192b482cf 100755
--- a/configure
+++ b/configure
@@ -29578,6 +29578,72 @@ fi
 
 PANEL_CFLAGS=$(echo $PANEL_CFLAGS | sed 's/-D_XOPEN_SOURCE=600//g')
 
+if test "x$have_curses" = xno
+then :
+
+else case e in #(
+  e)
+          save_curses_cppflags=$CPPFLAGS
+  as_fn_append CPPFLAGS " $CURSES_CFLAGS"
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether curses supports wide characters" >&5
+printf %s "checking whether curses supports wide characters... " >&6; }
+if test ${ac_cv_curses_wide+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#define NCURSES_OPAQUE 0
+#if defined(HAVE_NCURSESW_NCURSES_H)
+#  include <ncursesw/ncurses.h>
+#elif defined(HAVE_NCURSESW_CURSES_H)
+#  include <ncursesw/curses.h>
+#elif defined(HAVE_NCURSES_NCURSES_H)
+#  include <ncurses/ncurses.h>
+#elif defined(HAVE_NCURSES_CURSES_H)
+#  include <ncurses/curses.h>
+#elif defined(HAVE_NCURSES_H)
+#  include <ncurses.h>
+#elif defined(HAVE_CURSES_H)
+#  include <curses.h>
+#endif
+
+int
+main (void)
+{
+
+        cchar_t wcval;
+        setcchar(&wcval, L"x", A_NORMAL, 0, NULL);
+        add_wch(&wcval);
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_curses_wide=yes
+else case e in #(
+  e) ac_cv_curses_wide=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_curses_wide" >&5
+printf "%s\n" "$ac_cv_curses_wide" >&6; }
+  CPPFLAGS=$save_curses_cppflags
+      if test "x$ac_cv_curses_wide" = xyes
+then :
+  printf "%s\n" "#define HAVE_NCURSESW 1" >>confdefs.h
+
+fi
+ ;;
+esac
+fi
+
 # On Solaris, term.h requires curses.h
 ac_fn_c_check_header_compile "$LINENO" "term.h" "ac_cv_header_term_h" "
 #define NCURSES_OPAQUE 0
diff --git a/configure.ac b/configure.ac
index 73d0bb48ea8f4f8..367234b6e9bf477 100644
--- a/configure.ac
+++ b/configure.ac
@@ -7194,6 +7194,33 @@ AS_VAR_IF([ac_sys_system], [Darwin], [
 dnl pyconfig.h defines _XOPEN_SOURCE=700
 PANEL_CFLAGS=$(echo $PANEL_CFLAGS | sed 's/-D_XOPEN_SOURCE=600//g')
 
+dnl A curses that is not named "ncursesw" can still be wide-character capable:
+dnl the system curses of NetBSD, or an ncurses built with --enable-widec that
+dnl keeps the plain name (pkgsrc, macOS).  Probe for the wide API and, if
+dnl present, build the module wide by defining HAVE_NCURSESW.
+AS_VAR_IF([have_curses], [no], [], [
+  dnl Use the adjusted CURSES_CFLAGS (e.g. macOS's -D_XOPEN_SOURCE_EXTENDED)
+  dnl so the wide-character declarations are visible to the probe.  This runs
+  dnl inside an outer WITH_SAVE_ENV, whose single CPPFLAGS save slot is not
+  dnl reentrant, so save and restore CPPFLAGS with a dedicated variable here.
+  save_curses_cppflags=$CPPFLAGS
+  AS_VAR_APPEND([CPPFLAGS], [" $CURSES_CFLAGS"])
+  AC_CACHE_CHECK([whether curses supports wide characters],
+    [ac_cv_curses_wide],
+    [AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM([_CURSES_INCLUDES], [[
+        cchar_t wcval;
+        setcchar(&wcval, L"x", A_NORMAL, 0, NULL);
+        add_wch(&wcval);
+      ]])],
+      [ac_cv_curses_wide=yes],
+      [ac_cv_curses_wide=no])])
+  CPPFLAGS=$save_curses_cppflags
+  dnl HAVE_NCURSESW marks the wide (cchar_t) curses API; its template comes
+  dnl from the ncursesw pkg-config check above, so no description here.
+  AS_VAR_IF([ac_cv_curses_wide], [yes], [AC_DEFINE([HAVE_NCURSESW], [1])])
+])
+
 # On Solaris, term.h requires curses.h
 AC_CHECK_HEADERS([term.h], [], [], _CURSES_INCLUDES)