diff --git a/backup/util/loggers/file_logger.class.php b/backup/util/loggers/file_logger.class.php
index e4ab4b1d824..5c05380d36f 100644
--- a/backup/util/loggers/file_logger.class.php
+++ b/backup/util/loggers/file_logger.class.php
@@ -75,7 +75,7 @@ class file_logger extends base_logger {
         if (substr($this->fullpath, -5) !== '.html') {
             $content = $prefix . str_repeat('  ', $depth) . $message . PHP_EOL;
         } else {
-            $content = $prefix . str_repeat('&nbsp;&nbsp;', $depth) . htmlentities($message, ENT_QUOTES) . '<br/>' . PHP_EOL;
+            $content = $prefix . str_repeat('&nbsp;&nbsp;', $depth) . htmlentities($message, ENT_QUOTES, 'UTF-8') . '<br/>' . PHP_EOL;
         }
         if (false === fwrite($this->fhandle, $content)) {
             throw new base_logger_exception('error_writing_file', $this->fullpath);
diff --git a/backup/util/loggers/output_indented_logger.class.php b/backup/util/loggers/output_indented_logger.class.php
index 8bb68113920..2eaea5b60a6 100644
--- a/backup/util/loggers/output_indented_logger.class.php
+++ b/backup/util/loggers/output_indented_logger.class.php
@@ -38,7 +38,7 @@ class output_indented_logger extends base_logger {
         if (defined('STDOUT')) {
             echo $prefix . str_repeat('  ', $depth) . $message . PHP_EOL;
         } else {
-            echo $prefix . str_repeat('&nbsp;&nbsp;', $depth) . htmlentities($message, ENT_QUOTES) . '<br/>' . PHP_EOL;
+            echo $prefix . str_repeat('&nbsp;&nbsp;', $depth) . htmlentities($message, ENT_QUOTES, 'UTF-8') . '<br/>' . PHP_EOL;
         }
         flush();
         return true;
diff --git a/backup/util/loggers/output_text_logger.class.php b/backup/util/loggers/output_text_logger.class.php
index fe61536c039..9d13dfdc63e 100644
--- a/backup/util/loggers/output_text_logger.class.php
+++ b/backup/util/loggers/output_text_logger.class.php
@@ -37,7 +37,7 @@ class output_text_logger extends base_logger {
         if (defined('STDOUT')) {
             echo $prefix . $message . PHP_EOL;
         } else {
-            echo $prefix . htmlentities($message, ENT_QUOTES) . '<br/>' . PHP_EOL;
+            echo $prefix . htmlentities($message, ENT_QUOTES, 'UTF-8') . '<br/>' . PHP_EOL;
         }
         flush();
         return true;
diff --git a/cache/classes/definition.php b/cache/classes/definition.php
index 607f0743a36..e278bbbec21 100644
--- a/cache/classes/definition.php
+++ b/cache/classes/definition.php
@@ -750,7 +750,7 @@ class cache_definition {
             if (!empty($this->identifiers)) {
                 $identifiers = array();
                 foreach ($this->identifiers as $key => $value) {
-                    $identifiers[] = htmlentities($key).'='.htmlentities($value);
+                    $identifiers[] = htmlentities($key, ENT_QUOTES, 'UTF-8').'='.htmlentities($value, ENT_QUOTES, 'UTF-8');
                 }
                 $this->keyprefixmulti['identifiers'] = join('&', $identifiers);
             }
diff --git a/lib/datalib.php b/lib/datalib.php
index 454bc7ec7b8..bd917ba1b69 100644
--- a/lib/datalib.php
+++ b/lib/datalib.php
@@ -1802,7 +1802,7 @@ function add_to_log($courseid, $module, $action, $url='', $info='', $cm=0, $user
     $timenow = time();
     $info = $info;
     if (!empty($url)) { // could break doing html_entity_decode on an empty var.
-        $url = html_entity_decode($url);
+        $url = html_entity_decode($url, ENT_QUOTES, 'UTF-8');
     } else {
         $url = '';
     }
diff --git a/lib/dml/pdo_moodle_database.php b/lib/dml/pdo_moodle_database.php
index 4aae9ce6ed6..61b161c156d 100644
--- a/lib/dml/pdo_moodle_database.php
+++ b/lib/dml/pdo_moodle_database.php
@@ -172,7 +172,7 @@ abstract class pdo_moodle_database extends moodle_database {
      * Function to print/save/ignore debugging messages related to SQL queries.
      */
     protected function debug_query($sql, $params = null) {
-        echo '<hr /> (', $this->get_dbtype(), '): ',  htmlentities($sql);
+        echo '<hr /> (', $this->get_dbtype(), '): ',  htmlentities($sql, ENT_QUOTES, 'UTF-8');
         if($params) {
             echo ' (parameters ';
             print_r($params);
diff --git a/lib/filelib.php b/lib/filelib.php
index 6c935efdfd6..ab120b39593 100644
--- a/lib/filelib.php
+++ b/lib/filelib.php
@@ -2286,7 +2286,7 @@ function send_file($path, $filename, $lifetime = 'default' , $filter=0, $pathiss
             $options = new stdClass();
             $options->newlines = false;
             $options->noclean = true;
-            $text = htmlentities($pathisstring ? $path : implode('', file($path)));
+            $text = htmlentities($pathisstring ? $path : implode('', file($path)), ENT_QUOTES, 'UTF-8');
             $output = '<pre>'. format_text($text, FORMAT_MOODLE, $options, $COURSE->id) .'</pre>';
 
             readstring_accel($output, $mimetype, false);
diff --git a/lib/navigationlib.php b/lib/navigationlib.php
index 3ac2a8b0cad..b4e69c6557c 100644
--- a/lib/navigationlib.php
+++ b/lib/navigationlib.php
@@ -3389,9 +3389,9 @@ class settings_navigation extends navigation_node {
                         continue;
                     }
                     if ($type->modclass == MOD_CLASS_RESOURCE) {
-                        $resources[html_entity_decode($type->type)] = $type->typestr;
+                        $resources[html_entity_decode($type->type, ENT_QUOTES, 'UTF-8')] = $type->typestr;
                     } else {
-                        $activities[html_entity_decode($type->type)] = $type->typestr;
+                        $activities[html_entity_decode($type->type, ENT_QUOTES, 'UTF-8')] = $type->typestr;
                     }
                 }
             } else {
@@ -4275,7 +4275,7 @@ class navigation_json {
         }
 
         if ($child->forcetitle || $child->title !== $child->text) {
-            $attributes['title'] = htmlentities($child->title);
+            $attributes['title'] = htmlentities($child->title, ENT_QUOTES, 'UTF-8');
         }
         if (array_key_exists($child->key.':'.$child->type, $this->expandable)) {
             $attributes['expandable'] = $child->key;
diff --git a/mod/wiki/pagelib.php b/mod/wiki/pagelib.php
index 2616c4f9555..507c4c7fd04 100644
--- a/mod/wiki/pagelib.php
+++ b/mod/wiki/pagelib.php
@@ -656,7 +656,7 @@ class page_wiki_comments extends page_wiki {
                     $parsedcontent = wiki_parse_content('nwiki', $comment->content, $options);
                 }
 
-                $cell4->text = format_text(html_entity_decode($parsedcontent['parsed_text']), FORMAT_HTML);
+                $cell4->text = format_text(html_entity_decode($parsedcontent['parsed_text'], ENT_QUOTES, 'UTF-8'), FORMAT_HTML);
             } else {
                 $cell4->text = format_text($comment->content, FORMAT_HTML);
             }
diff --git a/mod/wiki/parser/utils.php b/mod/wiki/parser/utils.php
index eb14bc07657..f777f28058d 100644
--- a/mod/wiki/parser/utils.php
+++ b/mod/wiki/parser/utils.php
@@ -14,9 +14,9 @@ require_once($CFG->dirroot . "/lib/outputcomponents.php");
 class parser_utils {
         
     public static function h($tag, $text = null, $options = array(), $escape_text = false) {
-        $tag = htmlentities($tag);
+        $tag = htmlentities($tag, ENT_COMPAT, 'UTF-8');
         if(!empty($text) && $escape_text) {
-                $text = htmlentities($text);
+                $text = htmlentities($text, ENT_COMPAT, 'UTF-8');
             }
         return html_writer::tag($tag, $text, $options);
     }