diff --git a/src/Illuminate/Database/Eloquent/Concerns/GuardsAttributes.php b/src/Illuminate/Database/Eloquent/Concerns/GuardsAttributes.php
index e89f65d1cdbb..d663a3835547 100644
--- a/src/Illuminate/Database/Eloquent/Concerns/GuardsAttributes.php
+++ b/src/Illuminate/Database/Eloquent/Concerns/GuardsAttributes.php
@@ -27,6 +27,13 @@ trait GuardsAttributes
      */
     protected static $unguarded = false;
 
+    /**
+     * The actual columns that exist on the database and can be guarded.
+     *
+     * @var array
+     */
+    protected static $guardableColumns = [];
+
     /**
      * Get the fillable attributes for the model.
      *
@@ -164,12 +171,30 @@ public function isFillable($key)
      */
     public function isGuarded($key)
     {
-        if (strpos($key, '->') !== false) {
-            $key = Str::before($key, '->');
+        if (empty($this->getGuarded())) {
+            return false;
         }
 
         return $this->getGuarded() == ['*'] ||
-               ! empty(preg_grep('/^'.preg_quote($key).'$/i', $this->getGuarded()));
+               ! empty(preg_grep('/^'.preg_quote($key).'$/i', $this->getGuarded())) ||
+               ! $this->isGuardableColumn($key);
+    }
+
+    /**
+     * Determine if the given column is a valid, guardable column.
+     *
+     * @param  string  $key
+     * @return bool
+     */
+    protected function isGuardableColumn($key)
+    {
+        if (! isset(static::$guardableColumns[get_class($this)])) {
+            static::$guardableColumns[get_class($this)] = $this->getConnection()
+                        ->getSchemaBuilder()
+                        ->getColumnListing($this->getTable());
+        }
+
+        return in_array($key, static::$guardableColumns[get_class($this)]);
     }
 
     /**
diff --git a/tests/Database/DatabaseEloquentModelTest.php b/tests/Database/DatabaseEloquentModelTest.php
index f0e56677fd64..acb9598ea8c8 100755
--- a/tests/Database/DatabaseEloquentModelTest.php
+++ b/tests/Database/DatabaseEloquentModelTest.php
@@ -10,6 +10,7 @@
 use Illuminate\Contracts\Events\Dispatcher;
 use Illuminate\Database\Connection;
 use Illuminate\Database\ConnectionResolverInterface;
+use Illuminate\Database\ConnectionResolverInterface as Resolver;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\JsonEncodingException;
@@ -1014,11 +1015,21 @@ public function testUnderscorePropertiesAreNotFilled()
     public function testGuarded()
     {
         $model = new EloquentModelStub;
+
+        EloquentModelStub::setConnectionResolver($resolver = m::mock(Resolver::class));
+        $resolver->shouldReceive('connection')->andReturn($connection = m::mock(stdClass::class));
+        $connection->shouldReceive('getSchemaBuilder->getColumnListing')->andReturn(['name', 'age', 'foo']);
+
         $model->guard(['name', 'age']);
         $model->fill(['name' => 'foo', 'age' => 'bar', 'foo' => 'bar']);
         $this->assertFalse(isset($model->name));
         $this->assertFalse(isset($model->age));
         $this->assertSame('bar', $model->foo);
+
+        $model = new EloquentModelStub;
+        $model->guard(['name', 'age']);
+        $model->fill(['Foo' => 'bar']);
+        $this->assertFalse(isset($model->Foo));
     }
 
     public function testFillableOverridesGuarded()
@@ -2134,7 +2145,7 @@ public function getDates()
 class EloquentModelSaveStub extends Model
 {
     protected $table = 'save_stub';
-    protected $guarded = ['id'];
+    protected $guarded = [];
 
     public function save(array $options = [])
     {