Place this code in custom_functions.php:

remove_action('thesis_hook_before_header', 'thesis_nav_menu');
add_action('thesis_hook_after_header', 'thesis_nav_menu');

Replace Nav Menu ∞

If you’ve written your own custom nav menu function, or you want to use a plugin such as the Multi-Level Navigation Plugin, you can remove the default menu and call in the new function instead.

Place this code in custom_functions.php (replacing my_nav_menu with the name of the new function you’ve created):

remove_action('thesis_hook_before_header', 'thesis_nav_menu');
add_action('thesis_hook_after_header', 'my_nav_menu');

Or, in the case of the Multi-Level Navigation Plugin, use its function name:

remove_action('thesis_hook_before_header', 'thesis_nav_menu');
add_action('thesis_hook_after_header', 'suckerfish');

Remove Nav Menu on Specific Pages Only ∞

Place this code in custom_functions.php (replace 6 with the desired page ID):

function remove_nav() {
  if (is_page('6'))
    remove_action('thesis_hook_before_header', 'thesis_nav_menu');
}

add_action('thesis_hook_before_html','remove_nav');

To remove the nav menu from multiple pages, use this code instead (replace 2, 7, and 46 with the desired page IDs):

function remove_nav() {
 if (is_page(array(2,7,46))) {
  remove_action('thesis_hook_before_header', 'thesis_nav_menu');
 }
}

add_action('thesis_hook_before_html', 'remove_nav');