diff --git a/src/Illuminate/Contracts/Database/Eloquent/ComparesCastableAttributes.php b/src/Illuminate/Contracts/Database/Eloquent/ComparesCastableAttributes.php
new file mode 100644
index 000000000000..5c9ad195b763
--- /dev/null
+++ b/src/Illuminate/Contracts/Database/Eloquent/ComparesCastableAttributes.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Illuminate\Contracts\Database\Eloquent;
+
+use Illuminate\Database\Eloquent\Model;
+
+interface ComparesCastableAttributes
+{
+    /**
+     * Determine if the given values are equal.
+     *
+     * @param  \Illuminate\Database\Eloquent\Model  $model
+     * @param  string  $key
+     * @param  mixed  $firstValue
+     * @param  mixed  $secondValue
+     * @return bool
+     */
+    public function compare(Model $model, string $key, mixed $firstValue, mixed $secondValue);
+}
diff --git a/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php b/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
index d5b6fdd23a00..a56cfe4ca575 100644
--- a/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
+++ b/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
@@ -990,6 +990,21 @@ protected function serializeClassCastableAttribute($key, $value)
         );
     }
 
+    /**
+     * Compare two values for the given attribute using the custom cast class.
+     *
+     * @param  string  $key
+     * @param  mixed  $original
+     * @param  mixed  $value
+     * @return bool
+     */
+    protected function compareClassCastableAttribute($key, $original, $value)
+    {
+        return $this->resolveCasterClass($key)->compare(
+            $this, $key, $original, $value
+        );
+    }
+
     /**
      * Determine if the cast type is a custom date time cast.
      *
@@ -1800,6 +1815,19 @@ protected function isClassSerializable($key)
             method_exists($this->resolveCasterClass($key), 'serialize');
     }
 
+    /**
+     * Determine if the key is comparable using a custom class.
+     *
+     * @param  string  $key
+     * @return bool
+     */
+    protected function isClassComparable($key)
+    {
+        return ! $this->isEnumCastable($key) &&
+            $this->isClassCastable($key) &&
+            method_exists($this->resolveCasterClass($key), 'compare');
+    }
+
     /**
      * Resolve the custom caster class for a given key.
      *
@@ -2265,6 +2293,8 @@ public function originalIsEquivalent($key)
             }
 
             return false;
+        } elseif ($this->isClassComparable($key)) {
+            return $this->compareClassCastableAttribute($key, $original, $attribute);
         }
 
         return is_numeric($attribute) && is_numeric($original)
diff --git a/tests/Database/EloquentModelCustomCastingTest.php b/tests/Database/EloquentModelCustomCastingTest.php
index c8487d5d1b95..a3f77227ecb6 100644
--- a/tests/Database/EloquentModelCustomCastingTest.php
+++ b/tests/Database/EloquentModelCustomCastingTest.php
@@ -6,6 +6,7 @@
 use GMP;
 use Illuminate\Contracts\Database\Eloquent\Castable;
 use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
+use Illuminate\Contracts\Database\Eloquent\ComparesCastableAttributes;
 use Illuminate\Contracts\Database\Eloquent\SerializesCastableAttributes;
 use Illuminate\Database\Capsule\Manager as DB;
 use Illuminate\Database\Eloquent\Model;
@@ -53,6 +54,11 @@ public function createSchema()
             $table->increments('id');
             $table->decimal('amount', 4, 2);
         });
+
+        $this->schema()->create('documents', function (Blueprint $table) {
+            $table->increments('id');
+            $table->json('document');
+        });
     }
 
     /**
@@ -64,6 +70,7 @@ protected function tearDown(): void
     {
         $this->schema()->drop('casting_table');
         $this->schema()->drop('members');
+        $this->schema()->drop('documents');
     }
 
     #[RequiresPhpExtension('gmp')]
@@ -176,6 +183,25 @@ public function testModelWithCustomCastsWorkWithCustomIncrementDecrement()
         $this->assertEquals('3.00', $model->amount->value);
     }
 
+    public function test_model_with_custom_casts_compare_function()
+    {
+        // Set raw attribute, this is an example of how we would receive JSON string from the database.
+        // Note the spaces after the colon.
+        $model = new Document();
+        $model->setRawAttributes(['document' => '{"content": "content", "title": "hello world"}']);
+        $model->save();
+
+        // Inverse title and content this would result in a different JSON string when json_encode is used
+        $document = new \stdClass();
+        $document->title = 'hello world';
+        $document->content = 'content';
+        $model->document = $document;
+
+        $this->assertFalse($model->isDirty('document'));
+        $document->title = 'hello world 2';
+        $this->assertTrue($model->isDirty('document'));
+    }
+
     /**
      * Get a database connection instance.
      *
@@ -410,3 +436,30 @@ class Member extends Model
         'amount' => Euro::class,
     ];
 }
+
+class Document extends Model
+{
+    public $timestamps = false;
+
+    protected $casts = [
+        'document' => StructuredDocumentCaster::class,
+    ];
+}
+
+class StructuredDocumentCaster implements CastsAttributes, ComparesCastableAttributes
+{
+    public function get($model, $key, $value, $attributes)
+    {
+        return json_decode($value);
+    }
+
+    public function set($model, $key, $value, $attributes)
+    {
+        return json_encode($value);
+    }
+
+    public function compare($model, $key, $value1, $value2)
+    {
+        return json_decode($value1) == json_decode($value2);
+    }
+}