diff --git a/docs/guide/input-validation.md b/docs/guide/input-validation.md
index 0122046ed7..981657b7ba 100644
--- a/docs/guide/input-validation.md
+++ b/docs/guide/input-validation.md
@@ -518,7 +518,7 @@ class StatusValidator extends Validator
     public function clientValidateAttribute($model, $attribute, $view)
     {
         $statuses = json_encode(Status::find()->select('id')->asArray()->column());
-        $message = json_encode($this->message);
+        $message = json_encode($this->message, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
         return <<<JS
 if (!$.inArray(value, $statuses)) {
     messages.push($message);
diff --git a/extensions/gii/generators/extension/Generator.php b/extensions/gii/generators/extension/Generator.php
index 7c719a6f7a..6e95630cc7 100644
--- a/extensions/gii/generators/extension/Generator.php
+++ b/extensions/gii/generators/extension/Generator.php
@@ -231,7 +231,7 @@ EOD;
      */
     public function getKeywordsArrayJson()
     {
-        return json_encode(explode(',', $this->keywords));
+        return json_encode(explode(',', $this->keywords), JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
     }
 
     /**
diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 3a3509e218..1215482f88 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -8,6 +8,8 @@ Yii Framework 2 Change Log
 - Bug #5584: `yii\rbac\DbRbacManager` should not delete items when deleting a rule on a database not supporting cascade update (mdmunir)
 - Bug #5601: Simple conditions in Query::where() and ActiveQuery::where() did not allow `yii\db\Expression` to be used as the value (cebe, stevekr)
 - Bug: Gii console command help information does not contain global options (qiangxue)
+- Enh #5587: `json_encode` is now used with `JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE` where it makes sense, also
+  it is now default for `Json::encode()` (samdark)
 - Enh #5600: Allow configuring debug panels in `yii\debug\Module::panels` as panel class name strings (qiangxue)
 - Enh #5613: Added `--overwrite` option to Gii console command to support overwriting all files (motin, qiangxue)
 - Enh #5646: Call `yii\base\ErrorHandler::unregister()` instead of `restore_*_handlers` directly (aivus)
diff --git a/framework/captcha/CaptchaAction.php b/framework/captcha/CaptchaAction.php
index ac9d5e9b3b..f4febbd01b 100644
--- a/framework/captcha/CaptchaAction.php
+++ b/framework/captcha/CaptchaAction.php
@@ -127,7 +127,7 @@ class CaptchaAction extends Action
                 // we add a random 'v' parameter so that FireFox can refresh the image
                 // when src attribute of image tag is changed
                 'url' => Url::to([$this->id, 'v' => uniqid()]),
-            ]);
+            ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
         } else {
             $this->setHttpHeaders();
             Yii::$app->response->format = Response::FORMAT_RAW;
diff --git a/framework/captcha/CaptchaValidator.php b/framework/captcha/CaptchaValidator.php
index 7d122b3c24..14a14abe65 100644
--- a/framework/captcha/CaptchaValidator.php
+++ b/framework/captcha/CaptchaValidator.php
@@ -103,6 +103,6 @@ class CaptchaValidator extends Validator
 
         ValidationAsset::register($view);
 
-        return 'yii.validation.captcha(value, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.captcha(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 }
diff --git a/framework/grid/CheckboxColumn.php b/framework/grid/CheckboxColumn.php
index 994600a6e3..7be244dbbf 100644
--- a/framework/grid/CheckboxColumn.php
+++ b/framework/grid/CheckboxColumn.php
@@ -84,7 +84,7 @@ class CheckboxColumn extends Column
             'name' => $this->name,
             'multiple' => $this->multiple,
             'checkAll' => $name,
-        ]);
+        ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
         $this->grid->getView()->registerJs("jQuery('#$id').yiiGridView('setSelectionColumn', $options);");
 
         if ($this->header !== null || !$this->multiple) {
@@ -104,7 +104,7 @@ class CheckboxColumn extends Column
         } else {
             $options = $this->checkboxOptions;
             if (!isset($options['value'])) {
-                $options['value'] = is_array($key) ? json_encode($key) : $key;
+                $options['value'] = is_array($key) ? json_encode($key, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) : $key;
             }
         }
 
diff --git a/framework/helpers/BaseJson.php b/framework/helpers/BaseJson.php
index fa2e8e32e1..cf3dc4f5cd 100644
--- a/framework/helpers/BaseJson.php
+++ b/framework/helpers/BaseJson.php
@@ -28,10 +28,10 @@ class BaseJson
      * represented in terms of a [[JsExpression]] object.
      * @param mixed $value the data to be encoded
      * @param integer $options the encoding options. For more details please refer to
-     * <http://www.php.net/manual/en/function.json-encode.php>.
+     * <http://www.php.net/manual/en/function.json-encode.php>. Default is `JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE`.
      * @return string the encoding result
      */
-    public static function encode($value, $options = 0)
+    public static function encode($value, $options = 320)
     {
         $expressions = [];
         $value = static::processData($value, $expressions, uniqid());
diff --git a/framework/validators/BooleanValidator.php b/framework/validators/BooleanValidator.php
index 2b902c86dc..09b45f3c3b 100644
--- a/framework/validators/BooleanValidator.php
+++ b/framework/validators/BooleanValidator.php
@@ -87,6 +87,6 @@ class BooleanValidator extends Validator
 
         ValidationAsset::register($view);
 
-        return 'yii.validation.boolean(value, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.boolean(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 }
diff --git a/framework/validators/CompareValidator.php b/framework/validators/CompareValidator.php
index d96964b443..70bc3ffd3a 100644
--- a/framework/validators/CompareValidator.php
+++ b/framework/validators/CompareValidator.php
@@ -229,6 +229,6 @@ class CompareValidator extends Validator
 
         ValidationAsset::register($view);
 
-        return 'yii.validation.compare(value, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.compare(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 }
diff --git a/framework/validators/FileValidator.php b/framework/validators/FileValidator.php
index 1dc536c01d..d43119c524 100644
--- a/framework/validators/FileValidator.php
+++ b/framework/validators/FileValidator.php
@@ -338,7 +338,7 @@ class FileValidator extends Validator
     {
         ValidationAsset::register($view);
         $options = $this->getClientOptions($object, $attribute);
-        return 'yii.validation.file(attribute, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.file(attribute, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 
     /**
diff --git a/framework/validators/ImageValidator.php b/framework/validators/ImageValidator.php
index 8ce23b6f07..6643c6ceb0 100644
--- a/framework/validators/ImageValidator.php
+++ b/framework/validators/ImageValidator.php
@@ -166,7 +166,7 @@ class ImageValidator extends FileValidator
     {
         ValidationAsset::register($view);
         $options = $this->getClientOptions($object, $attribute);
-        return 'yii.validation.image(attribute, messages, ' . json_encode($options) . ', deferred);';
+        return 'yii.validation.image(attribute, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ', deferred);';
     }
 
     /**
diff --git a/framework/validators/RangeValidator.php b/framework/validators/RangeValidator.php
index 6ce9b2976e..370a1d5554 100644
--- a/framework/validators/RangeValidator.php
+++ b/framework/validators/RangeValidator.php
@@ -101,6 +101,6 @@ class RangeValidator extends Validator
 
         ValidationAsset::register($view);
 
-        return 'yii.validation.range(value, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.range(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 }
diff --git a/framework/validators/RequiredValidator.php b/framework/validators/RequiredValidator.php
index 9f8a119a72..3b57876a09 100644
--- a/framework/validators/RequiredValidator.php
+++ b/framework/validators/RequiredValidator.php
@@ -107,6 +107,6 @@ class RequiredValidator extends Validator
 
         ValidationAsset::register($view);
 
-        return 'yii.validation.required(value, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.required(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 }
diff --git a/framework/validators/StringValidator.php b/framework/validators/StringValidator.php
index a75a56a2a0..0ca40c6c69 100644
--- a/framework/validators/StringValidator.php
+++ b/framework/validators/StringValidator.php
@@ -183,6 +183,6 @@ class StringValidator extends Validator
 
         ValidationAsset::register($view);
 
-        return 'yii.validation.string(value, messages, ' . json_encode($options) . ');';
+        return 'yii.validation.string(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }
 }
diff --git a/framework/web/User.php b/framework/web/User.php
index 96baf99b6b..e4640409db 100644
--- a/framework/web/User.php
+++ b/framework/web/User.php
@@ -538,7 +538,7 @@ class User extends Component
             $identity->getId(),
             $identity->getAuthKey(),
             $duration,
-        ]);
+        ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
         $cookie->expire = time() + $duration;
         Yii::$app->getResponse()->getCookies()->add($cookie);
     }
diff --git a/framework/widgets/ListView.php b/framework/widgets/ListView.php
index 107c6b616f..dc8e79ffff 100644
--- a/framework/widgets/ListView.php
+++ b/framework/widgets/ListView.php
@@ -101,7 +101,7 @@ class ListView extends BaseListView
         $options = $this->itemOptions;
         $tag = ArrayHelper::remove($options, 'tag', 'div');
         if ($tag !== false) {
-            $options['data-key'] = is_array($key) ? json_encode($key) : (string) $key;
+            $options['data-key'] = is_array($key) ? json_encode($key, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) : (string) $key;
 
             return Html::tag($tag, $content, $options);
         } else {