diff --git a/lib/classes/output/mustache_template_source_loader.php b/lib/classes/output/mustache_template_source_loader.php
index 826f814cde2..39d6bd8ebc3 100644
--- a/lib/classes/output/mustache_template_source_loader.php
+++ b/lib/classes/output/mustache_template_source_loader.php
@@ -319,17 +319,9 @@ class mustache_template_source_loader {
                         break;
                     case Mustache_Tokenizer::T_SECTION:
                         if ($name == 'str') {
-                            // The token that containts the string identifiers (key and component) should
-                            // immediately follow the #str token.
-                            $identifiertoken = isset($tokens[$index + 1]) ? $tokens[$index + 1] : null;
+                            list($id, $component) = $this->get_string_identifiers($tokens, $index);
 
-                            if ($identifiertoken) {
-                                // The string identifier is the key and component comma separated.
-                                $identifierstring = $identifiertoken['value'];
-                                $parts = explode(',', $identifierstring);
-                                $id = $parts[0];
-                                // Default to 'core' for the component, if not specified.
-                                $component = isset($parts[1]) ? $parts[1] : 'core';
+                            if ($id) {
                                 $strings = $addtodependencies($strings, $component, $id);
                             }
                         }
@@ -343,4 +335,50 @@ class mustache_template_source_loader {
             'strings' => $strings
         ];
     }
+
+    /**
+     * Gets the identifier and component of the string.
+     *
+     * The string could be defined on one, or multiple lines.
+     *
+     * @param array $tokens The templates token.
+     * @param int $start The index of the start of the string token.
+     * @return array A list of the string identifier and component.
+     */
+    protected function get_string_identifiers(array $tokens, int $start): array {
+        $current = $start + 1;
+        $parts = [];
+
+        // Get the contents of the string tag.
+        while ($tokens[$current]['type'] !== Mustache_Tokenizer::T_END_SECTION) {
+            if (!isset($tokens[$current]['value']) || empty(trim($tokens[$current]['value']))) {
+                // An empty line, so we should ignore it.
+                $current++;
+                continue;
+            }
+
+            // We need to remove any spaces before and after the string.
+            $nospaces = trim($tokens[$current]['value']);
+
+            // We need to remove any trailing commas so that the explode will not add an
+            // empty entry where two paramters are on multiple lines.
+            $clean = rtrim($nospaces, ',');
+
+            // We separate the parts of a string with commas.
+            $subparts = explode(',', $clean);
+
+            // Store the parts.
+            $parts = array_merge($parts, $subparts);
+
+            $current++;
+        }
+
+        // The first text should be the first part of a str tag.
+        $id = isset($parts[0]) ? trim($parts[0]) : null;
+
+        // Default to 'core' for the component, if not specified.
+        $component = isset($parts[1]) ? trim($parts[1]) : 'core';
+
+        return [$id, $component];
+    }
 }
diff --git a/lib/tests/mustache_template_source_loader_test.php b/lib/tests/mustache_template_source_loader_test.php
index 1ccac41b1e5..a0e30db7b16 100644
--- a/lib/tests/mustache_template_source_loader_test.php
+++ b/lib/tests/mustache_template_source_loader_test.php
@@ -357,12 +357,43 @@ TBC;
         $bar = '{{! a comment }}{{> core/baz }}';
         $baz = '{{! a comment }}{{#str}} hide, core {{/str}}';
         $bop = '{{! a comment }}hello';
+        $multiline1 = <<<TEMPLATE
+{{! a comment }}{{#str}} authorreplyingprivatelytoauthor,
+mod_forum {{/str}}
+TEMPLATE;
+        $multiline2 = <<<TEMPLATE
+{{! a comment }}{{#str}}
+authorreplyingprivatelytoauthor,
+mod_forum {{/str}}
+TEMPLATE;
+        $multiline3 = <<<TEMPLATE
+{{! a comment }}{{#str}}
+authorreplyingprivatelytoauthor,
+mod_forum
+{{/str}}
+TEMPLATE;
+        $multiline4 = <<<TEMPLATE
+{{! a comment }}{{#str}}
+authorreplyingprivatelytoauthor, mod_forum
+{{/str}}
+TEMPLATE;
+        $multiline5 = <<<TEMPLATE
+{{! a comment }}{{#str}}
+hide
+{{/str}}
+TEMPLATE;
+
         $cache = [
             'core' => [
                 'foo' => $foo,
                 'bar' => $bar,
                 'baz' => $baz,
-                'bop' => $bop
+                'bop' => $bop,
+                'multiline1' => $multiline1,
+                'multiline2' => $multiline2,
+                'multiline3' => $multiline3,
+                'multiline4' => $multiline4,
+                'multiline5' => $multiline5,
             ]
         ];
         $loader = $this->build_loader_from_static_cache($cache);
@@ -409,6 +440,56 @@ TBC;
                     ]
                 ]
             ],
+            'string: component on new line' => [
+                'loader' => $loader,
+                'source' => $multiline1,
+                'expected' => [
+                    'templates' => [],
+                    'strings' => [
+                        'mod_forum' => ['authorreplyingprivatelytoauthor']
+                    ]
+                ]
+            ],
+            'string: identifier on own line' => [
+                'loader' => $loader,
+                'source' => $multiline2,
+                'expected' => [
+                    'templates' => [],
+                    'strings' => [
+                        'mod_forum' => ['authorreplyingprivatelytoauthor']
+                    ]
+                ]
+            ],
+            'string: all parts on new lines' => [
+                'loader' => $loader,
+                'source' => $multiline3,
+                'expected' => [
+                    'templates' => [],
+                    'strings' => [
+                        'mod_forum' => ['authorreplyingprivatelytoauthor']
+                    ]
+                ]
+            ],
+            'string: id and component on own line' => [
+                'loader' => $loader,
+                'source' => $multiline4,
+                'expected' => [
+                    'templates' => [],
+                    'strings' => [
+                        'mod_forum' => ['authorreplyingprivatelytoauthor']
+                    ]
+                ]
+            ],
+            'string: no component' => [
+                'loader' => $loader,
+                'source' => $multiline5,
+                'expected' => [
+                    'templates' => [],
+                    'strings' => [
+                        'core' => ['hide']
+                    ]
+                ]
+            ],
         ];
     }