diff --git a/menu_block.admin.inc b/menu_block.admin.inc
index eda4fd6..a41920a 100644
--- a/menu_block.admin.inc
+++ b/menu_block.admin.inc
@@ -382,6 +382,13 @@ function menu_block_configure_form($form, &$form_state) {
     '#default_value' => $config['sort'],
     '#description' => t('Sort each item in the active trail to the top of its level. When used on a deep or wide menu tree, the active menu item’s children will be easier to see when the page is reloaded.'),
   );
+  $form['hide_siblings'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('<strong>Hide siblings</strong> of the active menu item’s trail.'),
+    '#default_value' => $config['hide_siblings'],
+    '#description' => t('If a menu item isn\'t in the active trail, don\'t show it.'),
+  );
+
   $form['parent'] = array(
     '#type' => 'select',
     '#title' => t('Fixed parent item'),
@@ -398,7 +405,7 @@ function menu_block_configure_form($form, &$form_state) {
   foreach (array('title_link', 'follow', 'depth_relative', 'follow_parent', 'expanded', 'sort', 'parent') as $key) {
     $form[$key]['#states']['visible'][':input[name=display_options]'] = array('value' => 'advanced');
   }
-  if ($config['title_link'] || $follow || $config['expanded'] || $config['sort'] || $config['parent_mlid']) {
+  if ($config['title_link'] || $follow || $config['expanded'] || $config['sort'] || $config['hide_siblings'] || $config['parent_mlid']) {
     $form['display_options']['#default_value'] = 'advanced';
   }
 
@@ -447,6 +454,7 @@ function _menu_block_block_save($delta = '', $edit = array()) {
       variable_set("menu_block_{$delta}_depth_relative", $edit['depth_relative']);
       variable_set("menu_block_{$delta}_expanded", $edit['expanded']);
       variable_set("menu_block_{$delta}_sort", $edit['sort']);
+      variable_set("menu_block_{$delta}_hide_siblings", $edit['hide_siblings']);
     }
   }
 }
diff --git a/menu_block.module b/menu_block.module
index a5bf396..17e93f1 100644
--- a/menu_block.module
+++ b/menu_block.module
@@ -245,6 +245,8 @@ function menu_block_default_config() {
     'depth_relative' => 0,
     'expanded' => 0,
     'sort' => 0,
+    'hide_siblings' => 0,
+    'active_depth' => array(),
   );
 }
 
@@ -411,6 +413,12 @@ function menu_tree_block_data(array &$config) {
   if ($config['sort']) {
     menu_tree_sort_active_path($tree);
   }
+  
+ // When hiding siblings, sort the active path & set the initial active depth.
+ if ($config['hide_siblings']) {
+   menu_tree_sort_active_path($tree);
+   $config['active_depth'][0] = 1;
+ }
 
   return $tree;
 }
@@ -801,7 +809,31 @@ function menu_block_tree_output(array &$tree, array $config = array()) {
   }
   $hook_delta = str_replace('-', '_', $config['delta']);
   $hook_menu_name = str_replace('-', '_', $config['menu_name']);
-
+  
+  //
+  // First, loop through the tree to get the depth of the current active item.
+  // If we don't do this, the depth of the current item won't be detected until
+  // we see the active item, which means lighter menu items never hide.
+  foreach ($tree as $key => $value) {
+    if ($config['hide_siblings']) {
+      // Build array of the active trails depth.
+      if (!empty($tree[$key]['link']['in_active_trail']) && $tree[$key]['link']['depth'] > 1) {
+        $config['active_depth'][] = $tree[$key]['link']['depth'];
+      }
+    }
+  }
+  // Loop through the tree and add a 'hidden' attribute to all non-active
+  // items at the same depth as the currently active menu item.
+  foreach ($tree as $key => $value) {
+    if ($config['hide_siblings']) {
+      // Hide menu items on the same depth but that are not in the active trail ie. active trail siblings.
+      if ( in_array($tree[$key]['link']['depth'], $config['active_depth']) && $tree[$key]['link']['in_active_trail'] == FALSE) {
+        $tree[$key]['link']['hidden'] = 1;
+      }
+    }
+  }
+    // Render all links that aren't hidden.
+  
   // Pull out just the menu links we are going to render so that we
   // get an accurate count for the first/last classes.
   foreach ($tree as $key => &$value) {
diff --git a/menu_block_export.admin.inc b/menu_block_export.admin.inc
index 8e487b8..8269ca8 100644
--- a/menu_block_export.admin.inc
+++ b/menu_block_export.admin.inc
@@ -83,6 +83,7 @@ function menu_block_export_form_submit(&$form, &$form_state) {
       'depth'       => {$config['depth']},
       'expanded'    => {$config['expanded']},
       'sort'        => {$config['sort']},
+      'hide_siblings' => {$config['hide_siblings']},
     ),
 END_OF_CONFIG;
   }