diff --git i/conditional_fields.module w/conditional_fields.module
index 56b65b5..ad6621e 100644
--- i/conditional_fields.module
+++ w/conditional_fields.module
@@ -210,6 +210,60 @@ function conditional_fields_element_info_alter(&$types) {
 }
 
 /**
+ * Implements hook_field_group_build_pre_render_alter()
+ * Have to wait for the group elements to be created - unfortunately this is after after_build
+ */
+function conditional_fields_field_group_build_pre_render_alter(&$element) {
+  // Have to re-process conditional fields over again for newly created 
+  // fieldgroup elements (and existing elements moved to fieldgroup children)
+
+  // $form_state is added to $form['#form_state'] via conditional_fields_form_after_build()
+  $form_state = $element['#form_state'];
+  $form_state['complete form'] = $element;
+  $form = &$form_state['complete form'];
+  // Loop through fieldgroups and fieldgroup children
+  $new_dependents = array();
+  foreach ($form['#fieldgroups'] as $group_name => $group) {
+    // Call element_after_build for fieldgroup children
+    foreach($group->children as $field_name) {
+      $parents = array_merge($group->array_parents, array($field_name));
+      $field_element = &drupal_array_get_nested_value($form, $parents);
+      conditional_fields_element_after_build($field_element, $form_state, TRUE);
+    }
+    // Call element_after_build for fieldgroup element
+    $group_element = &drupal_array_get_nested_value($form, $group->array_parents);
+    $group_element['#field_name'] = $group_name;
+    // Make sure group element has an ID to select in drupal_process_states
+    $group_element['#id'] = isset($group_element['#id']) ? $group_element['#id'] : $group_name;
+    // Need to wrap markup type with a div with the ID, unless ID already present in prefix or markup
+    if (isset($group_element['#type']) && $group_element['#type'] == 'markup') {
+      if ((!isset($group_element['#prefix']) || !strstr($group_element['#prefix'], '#' . $group_element['#id']))
+        && (!isset($group_element['#markup']) || !strstr($group_element['#markup'], '#' . $group_element['#id']))
+      ) {
+        $group_element['#prefix'] = '<div id="' . $group_element['#id'] . '">' . (isset($group_element['#prefix']) ? $group_element['#prefix'] : '');
+        $group_element['#suffix'] = (isset($group_element['#suffix']) ? $group_element['#suffix'] : '') . '</div>';
+      }
+    }
+    conditional_fields_element_after_build($group_element, $form_state, TRUE);
+    if (isset($form['#conditional_fields'][$group_name], $form['#conditional_fields'][$group_name]['dependees'])) {
+      $new_dependents[$group_name] = &$group_element;
+    }
+  }
+
+  // Call form_after_build
+  $form = conditional_fields_form_after_build($form, $form_state, TRUE);
+
+  // Call validation for group dependents
+  foreach ($new_dependents as $dependent_name => &$dependent) {
+    conditional_fields_dependent_validate($dependent, $form_state, $form);
+  }
+  // Call form validation
+  conditional_fields_form_validate($form, $form_state);
+
+  $element = $form;
+}
+
+/**
  * Processes form elements with dependencies.
  *
  * Just adds a #conditional_fields property to the form with the needed
@@ -217,7 +271,7 @@ function conditional_fields_element_info_alter(&$types) {
  * - The fields #parents property.
  * - Field dependencies data.
  */
-function conditional_fields_element_after_build($element, &$form_state) {
+function conditional_fields_element_after_build($element, &$form_state, $reprocess = FALSE) {  
   // Ensure that the element is a field.
   if (isset($element['#field_name'])) {
     $field = $element;
@@ -237,6 +291,10 @@ function conditional_fields_element_after_build($element, &$form_state) {
     return $element;
   }
 
+  // Get fieldgroup name if field belongs to one
+  $group_name = isset($form['#group_children']) && isset($form['#group_children'][$field['#field_name']]) ? 
+    $form['#group_children'][$field['#field_name']] : NULL;
+
   // Some fields do not have entity type and bundle properties. In this case we
   // try to use the properties from the form. This is not an optimal solution,
   // since in case of fields in entities within entities they might not correspond,
@@ -262,11 +320,24 @@ function conditional_fields_element_after_build($element, &$form_state) {
   // Attach dependent.
   if (isset($dependencies['dependents'][$field['#field_name']])) {
     foreach ($dependencies['dependents'][$field['#field_name']] as $id => $dependency) {
-      if (!isset($form['#conditional_fields'][$field['#field_name']]['dependees'][$id])) {
+      if ($reprocess || !isset($form['#conditional_fields'][$field['#field_name']]['dependees'][$id])) {
         conditional_fields_attach_dependency($form, array('#field_name' => $dependency['dependee']), $field, $dependency['options'], $id);
       }
     }
   }
+  // Also attach dependent if element is a (first) child in a dependent fieldgroup
+  // and the dependency state isn't 'visible' or 'hidden' 
+  // (this is done on the fieldgroup element itself)
+  if ($group_name && isset($dependencies['dependents'][$group_name]) ) {
+    $group_dependent = $dependencies['dependents'][$group_name];
+    if (!in_array($group_dependent[key($group_dependent)]['options']['state'], array('visible', 'hidden'))) {
+      foreach ($group_dependent as $id => $dependency) {
+        if ($reprocess || !isset($form['#conditional_fields'][$field['#field_name']]['dependees'][$id])) {
+          conditional_fields_attach_dependency($form, array('#field_name' => $dependency['dependee']), $field, $dependency['options'], $id);
+        }
+      }
+    }
+  }
 
   // Attach dependee.
   // TODO: collect information about every element of the dependee widget, not
@@ -274,7 +345,7 @@ function conditional_fields_element_after_build($element, &$form_state) {
   // define per-element sets of dependency values.
   if (isset($dependencies['dependees'][$field['#field_name']])) {
     foreach ($dependencies['dependees'][$field['#field_name']] as $id => $dependency) {
-      if (!isset($form['#conditional_fields'][$field['#field_name']]['dependents'][$id])) {
+      if ($reprocess || !isset($form['#conditional_fields'][$field['#field_name']]['dependents'][$id])) {
         conditional_fields_attach_dependency($form, $field, array('#field_name' => $dependency['dependent']), $dependency['options'], $id);
       }
     }
@@ -383,8 +454,10 @@ function conditional_fields_attach_dependency(&$form, $dependee, $dependent, $op
   // Attach dependee.
   // Use the #parents property of the dependee instead of #field_parents since
   // we will need access to the full structure of the widget.
+  // We also need #field_parents to get the field from $form
   if (isset($dependee['#parents'])) {
     $form['#conditional_fields'][$dependee['#field_name']]['parents'] = $dependee['#parents'];
+    $form['#conditional_fields'][$dependee['#field_name']]['array_parents'] = $dependee['#array_parents'];
     $form['#conditional_fields'][$dependee['#field_name']]['dependents'][$id] = array(
       'dependent' => $dependent['#field_name'],
       'options'   => $options,
@@ -400,6 +473,7 @@ function conditional_fields_attach_dependency(&$form, $dependee, $dependent, $op
   }
   if (isset($dependent_parents)) {
     $form['#conditional_fields'][$dependent['#field_name']]['field_parents'] = $dependent_parents;
+    $form['#conditional_fields'][$dependent['#field_name']]['array_parents'] = $dependent['#array_parents'];
     $form['#conditional_fields'][$dependent['#field_name']]['dependees'][$id] = array(
       'dependee' => $dependee['#field_name'],
       'options'  => $options,
@@ -424,6 +498,10 @@ function conditional_fields_form_after_build($form, &$form_state) {
     return $form;
   }
 
+  // Set $form_state in $form so hook_field_group_build_pre_render_alter has access to it
+  // when it is invoked after after_build (when fieldgroup elements are attached to form)
+  $form['#form_state'] =& $form_state;
+  
   $effects = array();
   $state_handlers = conditional_fields_states_handlers();
 
@@ -435,7 +513,8 @@ function conditional_fields_form_after_build($form, &$form_state) {
       continue;
     }
 
-    $dependent_location = array_merge($dependent_info['field_parents'], array($dependent));
+    // Here we use #array_parents to get field from $form
+    $dependent_location = $dependent_info['array_parents'];
     $dependent_form_field = drupal_array_get_nested_value($form, $dependent_location);
 
     // Cycle the dependant's dependees.
@@ -445,9 +524,16 @@ function conditional_fields_form_after_build($form, &$form_state) {
       if (empty($form['#conditional_fields'][$dependee])) {
         continue;
       }
+      // Skip this dependency if it's a group element and state is not visible/hidden
+      // (dependencies for other states are attached to fieldgroup children elements)
+      if (in_array($dependent_form_field['#field_name'], array_keys($form['#fieldgroups'])) && !in_array($dependency['options']['state'], array('visible', 'hidden'))) {
+        continue;
+      }
 
       $dependee_info = $form['#conditional_fields'][$dependee];
-      $dependee_form_field = drupal_array_get_nested_value($form, $dependee_info['parents']);
+      // Here we use #array_parents to get field from $form
+      $dependee_location = $dependee_info['array_parents'];
+      $dependee_form_field = drupal_array_get_nested_value($form, $dependee_location);
       $options = $dependency['options'];
 
       // Load field edit behaviors.
@@ -669,7 +755,12 @@ function conditional_fields_form_after_build($form, &$form_state) {
  * @see conditional_fields_form_validate()
  */
 function conditional_fields_dependent_validate($element, &$form_state, $form) {
-  $dependent = $element[$element['#language']];
+  if (isset($element['#language'], $element[$element['#language']])) {
+    $dependent = $element[$element['#language']];
+  }
+  else {
+    $dependent = $element;    
+  }
 
   // Check if this field's dependencies were triggered.
   if (conditional_fields_evaluate_dependencies($dependent, $form, $form_state)) {
@@ -691,7 +782,7 @@ function conditional_fields_dependent_validate($element, &$form_state, $form) {
   // conditional_fields_form_validate().
   $errors = form_get_errors();
 
-  if ($errors) {
+  if ($errors && isset($dependent['#parents'])) {  // group elements have no #parents key
     $error_key = implode('][', $dependent['#parents']);
     foreach ($errors as $name => $error) {
       // An error triggered by this field might have been set on a descendant
@@ -720,7 +811,9 @@ function conditional_fields_dependent_validate($element, &$form_state, $form) {
  */
 function conditional_fields_form_field_get_values($element, $form_state) {
   // Fall back to #parents to support custom dependencies.
-  $parents = isset($element['#field_parents']) ? $element['#field_parents'] : $element['#parents'];
+  // $parents = isset($element['#field_parents']) ? $element['#field_parents'] : $element['#parents'];
+  // Should this be the other way around? Isn't #parents the parent keys in $form_state['values']?
+  $parents = isset($element['#parents']) ? $element['#parents'] : $element['#field_parents'];
   return drupal_array_get_nested_value($form_state['values'], $parents);
 }
 
@@ -1001,7 +1094,7 @@ function conditional_fields_evaluate_dependencies($dependent, $form, $form_state
   foreach ($dependencies as $dependency_id => $dependency) {
     // Extract field values from submitted values.
     $dependee = $dependency['dependee'];
-    $dependee_parents = $form['#conditional_fields'][$dependee]['parents'];
+    $dependee_parents = $form['#conditional_fields'][$dependee]['array_parents'];
 
     // We have the parents of the field, but depending on the entity type and
     // the widget type, they may include additional elements that are actually
@@ -1266,21 +1359,34 @@ function conditional_fields_load_dependencies($entity_type = NULL, $bundle = NUL
     $default_options = conditional_fields_dependency_default_options();
 
     $select = db_select('conditional_fields', 'cf')
-      ->fields('cf', array('id', 'options'))
-      ->orderBy('cf.dependent');
+      ->fields('cf', array('id', 'options'));
     $fci_depende = $select->join('field_config_instance', 'fci_dependee', 'cf.dependee = fci_dependee.id');
-    $fci_dependent = $select->join('field_config_instance', 'fci_dependent', 'cf.dependent = fci_dependent.id');
     $select->addField($fci_depende, 'field_name', 'dependee');
-    $select->addField($fci_dependent, 'field_name', 'dependent');
     $select->addField($fci_depende, 'entity_type');
     $select->addField($fci_depende, 'bundle');
 
+    // Clone query now to allow a union with fieldgroup results
+    $select_group = clone $select;
+
+    // Join with field_config_instance
+    $fci_dependent = $select->join('field_config_instance', 'fci_dependent', 'cf.dependent = fci_dependent.id');
+    $select->addField($fci_dependent, 'field_name', 'dependent');
+
+    // Join with field_group
+    $group_dependent = $select_group->join('field_group', 'fg_dependent', 'cf.dependent = fg_dependent.id');
+    $select_group->addField($group_dependent, 'group_name', 'dependent');
+
     if ($entity_type) {
       $select->condition(
         db_and()
           ->condition('fci_dependee.entity_type', $entity_type)
           ->condition('fci_dependent.entity_type', $entity_type)
       );
+      $select_group->condition(
+        db_and()
+          ->condition('fci_dependee.entity_type', $entity_type)
+          ->condition('fg_dependent.entity_type', $entity_type)
+      );
     }
 
     if ($bundle) {
@@ -1289,7 +1395,15 @@ function conditional_fields_load_dependencies($entity_type = NULL, $bundle = NUL
           ->condition('fci_dependee.bundle', $bundle)
           ->condition('fci_dependent.bundle', $bundle)
       );
+      $select_group->condition(
+        db_and()
+          ->condition('fci_dependee.bundle', $bundle)
+          ->condition('fg_dependent.bundle', $bundle)
+      );
     }
+    // Union of results
+    //$select->orderBy('cf.dependent');
+    $select->union($select_group, 'UNION');
 
     $result = $select->execute();
 
diff --git i/includes/conditional_fields.admin.inc w/includes/conditional_fields.admin.inc
index bf790f0..308b475 100644
--- i/includes/conditional_fields.admin.inc
+++ w/includes/conditional_fields.admin.inc
@@ -106,6 +106,15 @@ function conditional_fields_dependencies_overview_page($bundle_name = NULL, $ent
 function conditional_fields_dependency_add_form($form, &$form_state, $entity_type, $bundle_name) {
   $form = array();
   $instances = field_info_instances($entity_type, $bundle_name);
+  // Get field groups on entity
+  $groups = field_group_info_groups($entity_type, $bundle_name);
+  $groups = isset($groups['form']) ? $groups['form'] : array();
+  foreach ($groups as $group_name => $group) {
+    $groups[$group_name] = (array)$group;
+  }
+  // New merged array of fields & groups for dependents
+  // Dependees should only be fields ($instances)
+  $instances_groups = $instances + $groups;
 
   if (count($instances) < 2) {
     $form['no_fields'] = array(
@@ -163,7 +172,7 @@ function conditional_fields_dependency_add_form($form, &$form_state, $entity_typ
         // first row they will appear grouped.
         if ($first_row == TRUE) {
           $form['table']['dependencies'][$id]['dependent'] = array(
-            '#markup' => check_plain($instances[$dependent]['label']) . ' (' . $dependent . ')',
+            '#markup' => check_plain($instances_groups[$dependent]['label']) . ' (' . $dependent . ')',
             '#rowspan' => $dependee_count,
           );
 
@@ -191,7 +200,7 @@ function conditional_fields_dependency_add_form($form, &$form_state, $entity_typ
           $row['description']['#colspan'] = 2;
         }
 
-        $row['description']['#markup'] = conditional_fields_dependency_description($instances[$dependency['dependee']]['label'], $instances[$dependent]['label'], $dependency['options']);
+        $row['description']['#markup'] = conditional_fields_dependency_description($instances[$dependency['dependee']]['label'], $instances_groups[$dependent]['label'], $dependency['options']);
 
         $row['edit'] = array(
           '#type' => 'link',
@@ -221,6 +230,14 @@ function conditional_fields_dependency_add_form($form, &$form_state, $entity_typ
 
   asort($fields);
 
+  // Build list of available groups.
+  $fieldgroups = array();
+  foreach ($groups as $group_name => $group) {
+    $fieldgroups[$group['id']] = check_plain($group['label'] . ' (' . $group['group_name'] . ')');
+  }
+
+  asort($fieldgroups);
+
   // Build list of states.
   $states = array_map('drupal_strtolower', conditional_fields_states());
 
@@ -236,7 +253,7 @@ function conditional_fields_dependency_add_form($form, &$form_state, $entity_typ
       '#title' => t('Dependent'),
       '#title_display' => 'invisible',
       '#description' => t('Dependent'),
-      '#options' => $fields,
+      '#options' => $fields + $fieldgroups,
       '#prefix' => '<div class="add-new-placeholder">' . t('Add new dependency') . '</div>',
     ),
     'dependee' => array(