diff --git a/includes/charts.pages.inc b/includes/charts.pages.inc
index 88c28fd..f04e5cc 100644
--- a/includes/charts.pages.inc
+++ b/includes/charts.pages.inc
@@ -248,6 +248,23 @@ function charts_settings_form($form, $defaults = array(), $field_options = array
     '#default_value' => $options['xaxis_labels_rotation'],
     '#parents' => array_merge($parents, array('xaxis_labels_rotation')),
   );
+  $form['xaxis']['sort'] = array(
+    '#title' => t('Axis sorting'),
+    '#description' => t('Sort the values on the horizontal axis by the specified field. This should either be the label field, or a field that correlates with it, otherwise labels may be duplicated.'),
+    '#type' => 'select',
+    '#options' => array('' => t("Don't sort")) + $field_options,
+    '#default_value' => $options['xaxis_sort'],
+    '#parents' => array_merge($parents, array('xaxis_sort')),
+  );
+  $form['xaxis']['sort_order'] = array(
+    '#type' => 'select',
+    '#options' => array(
+      'asc' => t('Ascending'),
+      'desc' => t('Descending'),
+    ),
+    '#default_value' => $options['xaxis_sort_order'],
+    '#parents' => array_merge($parents, array('xaxis_sort_order')),
+  );
 
   $form['yaxis'] = array(
     '#title' => t('Vertical axis'),
@@ -397,6 +414,8 @@ function charts_default_settings() {
 
   $defaults['xaxis_title'] = '';
   $defaults['xaxis_labels_rotation'] = 0;
+  $defaults['xaxis_sort'] = '';
+  $defaults['xaxis_sort_order'] = 'asc';
 
   $defaults['yaxis_title'] = '';
   $defaults['yaxis_min'] = '';
diff --git a/views/charts_plugin_style_chart.inc b/views/charts_plugin_style_chart.inc
index fb143b0..ce8a79b 100644
--- a/views/charts_plugin_style_chart.inc
+++ b/views/charts_plugin_style_chart.inc
@@ -10,6 +10,14 @@
  * @ingroup views_style_plugins
  */
 class charts_plugin_style_chart extends views_plugin_style {
+
+  /**
+   * Maps Views result row numbers to their weights for charts with sorted axis.
+   *
+   * @var array
+   */
+  protected $row_weights = array();
+
   /**
    * Set default options.
    */
@@ -143,6 +151,12 @@ function render() {
       $label_field_key = $this->options['label_field'];
     }
 
+    // Same for the x-axis sorting field, if any.
+    $sort_field_key = NULL;
+    if ($this->options['xaxis_sort'] && array_key_exists($this->options['xaxis_sort'], $field_handlers)) {
+      $sort_field_key = $this->options['xaxis_sort'];
+    }
+
     // Assemble the fields to be used to provide data access.
     $data_field_options = array_filter($this->options['data_fields']);
     $data_fields = array();
@@ -229,6 +243,7 @@ function render() {
       $sets = $this->render_grouping($this->view->result, $this->options['grouping'], TRUE);
       $row_labels_inverted = array();
       $series_keys = array();
+      $this->row_weights = array();
       foreach ($sets as $series_label => $data_set) {
         $series_index = isset($series_index) ? $series_index + 1 : 0;
         $series_key = $this->view->current_display . '__' . $series_index;
@@ -258,6 +273,9 @@ function render() {
             }
             $row_number = $row_labels_inverted[$label];
           }
+          if ($sort_field_key && !isset($this->row_weights[$row_number])) {
+            $this->row_weights[$row_number] = $this->get_field($result_number, $sort_field_key);
+          }
           foreach ($data_fields as $field_key => $field_handler) {
             // Don't allow the grouping field to provide data.
             if (isset($this->options['grouping'][0]['field']) && $field_key === $this->options['grouping'][0]['field']) {
@@ -283,7 +301,19 @@ function render() {
         $default_values = array_fill_keys($row_labels_inverted, NULL);
         foreach ($series_keys as $series_key) {
           $chart[$series_key]['#data'] += $default_values;
-          ksort($chart[$series_key]['#data']);
+          // Sort the new data set by row number again, unless they will be
+          // sorted by custom weights afterwards anyways.
+          if (!$sort_field_key) {
+            ksort($chart[$series_key]['#data']);
+          }
+        }
+      }
+      if ($sort_field_key) {
+        uksort($chart['xaxis']['#labels'], array($this, 'compareRows'));
+        $chart['xaxis']['#labels'] = array_values($chart['xaxis']['#labels']);
+        foreach ($series_keys as $series_key) {
+          uksort($chart[$series_key]['#data'], array($this, 'compareRows'));
+          $chart[$series_key]['#data'] = array_values($chart[$series_key]['#data']);
         }
       }
     }
@@ -354,6 +384,35 @@ function render() {
   }
 
   /**
+   * Compares two row numbers to see which should be ordered first.
+   *
+   * @param int $a
+   *   The first row index.
+   * @param int $b
+   *   The second row index.
+   *
+   * @return int
+   *   -1, 0 or 1 if the first result row's sort weight is less than, equal to
+   *   or greater than the second's, respectively.
+   */
+  public function compareRows($a, $b) {
+    $sort_factor = $this->options['xaxis_sort_order'] == 'desc' ? -1 : 1;
+    $weight_a = isset($this->row_weights[$a]) ? $this->row_weights[$a] : 0;
+    $weight_b = isset($this->row_weights[$b]) ? $this->row_weights[$b] : 0;
+    // If weights are equal, preserve normal ordering by row numbers. (Necessary
+    // special case since PHP's built-in sorting functions aren't stable.)
+    if ($weight_a == $weight_b) {
+      $weight_a = $a;
+      $weight_b = $b;
+      $sort_factor = 1;
+      if ($weight_a == $weight_b) {
+        return 0;
+      }
+    }
+    return $sort_factor * ($weight_a < $weight_b ? -1 : 1);
+  }
+
+  /**
    * Utility function to check if this chart has a parent display.
    */
   function get_parent_chart_display() {