diff --git a/include/unistd.h b/include/unistd.h
index 10463f28b5dc1..3c576d6e1f99d 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -57,6 +57,9 @@
 #undef  _POSIX_MEMLOCK_RANGE
 #undef  _POSIX_FSYNC
 #define _POSIX_SYNCHRONIZED_IO 1
+#ifdef CONFIG_LIBC_PASSWD_LINESIZE
+#  define _POSIX_GETPW_R_SIZE_MAX CONFIG_LIBC_PASSWD_LINESIZE
+#endif
 
 #define _POSIX_VERSION 201712L
 #define _POSIX_PRIORITIZED_IO _POSIX_VERSION
diff --git a/libs/libc/unistd/lib_sysconf.c b/libs/libc/unistd/lib_sysconf.c
index eff4e718e2dc6..a35120e5d1a15 100644
--- a/libs/libc/unistd/lib_sysconf.c
+++ b/libs/libc/unistd/lib_sysconf.c
@@ -223,6 +223,10 @@ long sysconf(int name)
         return _POSIX_PRIORITIZED_IO;
       case _SC_AIO_MAX:
         return _POSIX_AIO_MAX;
+#ifdef CONFIG_LIBC_PASSWD_LINESIZE
+      case _SC_GETPW_R_SIZE_MAX:
+        return _POSIX_GETPW_R_SIZE_MAX;
+#endif
       case _SC_CPUTIME:
         return _POSIX_CPUTIME;
       case _SC_THREAD_CPUTIME: