diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 8b1c1787dc7c74fdb66780f59e4bc70d903ffd00..53040d9a9c531ddc7f570b0578cffd5508fa9224 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,5 +1,7 @@
 Search API 1.x, dev (xxxx-xx-xx):
 ---------------------------------
+- #2932347 by drunken monkey, ghaya: Fixed case insensitive matching for
+  highlighting non-ASCII text.
 - #2938288 by drunken monkey: Fixed problems with PHP 7.2.
 - #2934321 by Graber, drunken monkey: Fixed Views total for views with pager
   offset.
diff --git a/src/Plugin/search_api/processor/Highlight.php b/src/Plugin/search_api/processor/Highlight.php
index 9e23eb7f048702149be9d9afdb96e7985defc424..195b7d5746194fd1cd4abda75773f0dcafbcd895 100644
--- a/src/Plugin/search_api/processor/Highlight.php
+++ b/src/Plugin/search_api/processor/Highlight.php
@@ -472,16 +472,18 @@ class Highlight extends ProcessorPluginBase implements PluginFormInterface {
         // and ends with a space.
         $matches = [];
 
-        $found_position = FALSE;
         if (!$this->configuration['highlight_partial']) {
+          $found_position = FALSE;
           $regex = '/' . self::$boundary . preg_quote($key, '/') . self::$boundary . '/iu';
           if (preg_match($regex, ' ' . $text . ' ', $matches, PREG_OFFSET_CAPTURE, $look_start[$key])) {
             $found_position = $matches[0][1];
           }
         }
+        elseif (function_exists('mb_stripos')) {
+          $found_position = mb_stripos($text, $key, $look_start[$key], 'UTF-8');
+        }
         else {
-          $function = function_exists('mb_stripos') ? 'mb_stripos' : 'stripos';
-          $found_position = $function($text, $key, $look_start[$key]);
+          $found_position = stripos($text, $key, $look_start[$key]);
         }
         if ($found_position !== FALSE) {
           $look_start[$key] = $found_position + 1;
diff --git a/tests/src/Unit/Processor/HighlightTest.php b/tests/src/Unit/Processor/HighlightTest.php
index b62be7aec9f6d86a47c08c3bf52e7c24f2312e75..02d31b1588b9f84e6dd0a1c60a85e75351b0303d 100644
--- a/tests/src/Unit/Processor/HighlightTest.php
+++ b/tests/src/Unit/Processor/HighlightTest.php
@@ -356,18 +356,26 @@ class HighlightTest extends UnitTestCase {
    * @see \Drupal\Tests\search_api\Unit\Processor\HighlightTest::testPostprocessSearchResultsHighlightPartial()
    */
   public function postprocessSearchResultsHighlightPartialDataProvider() {
-    return [
+    $data_sets = [
       'normal' => [
         'Some longwordtoshowpartialmatching value',
         'partial',
         'Some longwordtoshow<strong>partial</strong>matching value',
       ],
-      'multi-byte' => [
+    ];
+
+    // Test multi-byte support only if this PHP installation actually contains
+    // the necessary function. Otherwise, we can't really be blamed for not
+    // supporting them.
+    if (function_exists('mb_stripos')) {
+      $data_sets['multi-byte'] = [
         'Alle Angaben ohne Gewähr.',
         'Ähr',
         'Alle Angaben ohne Gew<strong>ähr</strong>.',
-      ],
-    ];
+      ];
+    }
+
+    return $data_sets;
   }
 
   /**