list_pages

Dann mach es auf die umständliche Variante und exclude die Unterseiten:

Zitat

Exclude Pages from List
To exclude certain Pages from the list, for instance, Pages with ID numbers 17 and 38, use the exclude argument.

PHP

<ul>
<?php wp_list_pages('exclude=17,38&title_li=<h2>' . __('Pages') . '</h2>' ); ?>
</ul>

Note: The Page(s) is only excluded from this list; it can still be accessed from Administration > Manage > Pages by clicking that Page's "View" button. It can also be accessed by directly typing its URI in your web browser. Excluding a Page from the list will also exclude all of its SubPages (children) if there are any.

http://codex.wordpress.org/Template_Tags/wp_list_pages

Aber es gibt auch direkt einen Parameter dafür:

Zitat

depth
(integer) Numeric value for how many levels of hierarchy (sub-pages) to display. Defaults to 0 (display all pages).

Sähe dann also so aus:

<?php wp_list_pages('depth=1' ); ?>

bzw. mit dem obigen Code:

<?php wp_list_pages('title_li=&depth=1'); ?>

(ohne es überprüft zu haben)