diff --git a/src/Arrays/Arr.php b/src/Arrays/Arr.php
index 8045561..d70b5c1 100644
--- a/src/Arrays/Arr.php
+++ b/src/Arrays/Arr.php
@@ -1317,7 +1317,7 @@ public static function undot( $array ) {
 		$results = [];
 
 		foreach ( $array as $key => $value ) {
-			static::set( $results, $key, $value );
+			$results = static::set( $results, explode( '.', $key ), $value );
 		}
 
 		return $results;
diff --git a/tests/wpunit/UndotTest.php b/tests/wpunit/UndotTest.php
new file mode 100644
index 0000000..25218f2
--- /dev/null
+++ b/tests/wpunit/UndotTest.php
@@ -0,0 +1,105 @@
+<?php
+
+use StellarWP\Arrays\Arr;
+use StellarWP\Arrays\Tests\ArraysTestCase;
+
+class UndotTest extends ArraysTestCase
+{
+
+    public function setUp()
+    {
+        // before
+        parent::setUp();
+    }
+
+    public function tearDown()
+    {
+        parent::tearDown();
+    }
+
+    /**
+     * @test
+     */
+    public function it_properly_expands_array()
+    {
+        $dotted = [
+        'one.two.three.five.eight' => 'fibonacci',
+        ];
+
+        $expected = [
+			'one' => [
+				'two' => [
+					'three' => [
+						'five' => [
+							'eight' => 'fibonacci'
+						]
+					]
+				]
+			],
+        ];
+
+        $this->assertSame($expected, Arr::undot($dotted));
+    }
+
+    /**
+     * @test
+     */
+    public function it_expands_array_with_leaves()
+    {
+        $dotted = [
+        'one.first_leaf' => true,
+        'one.two.second_leaf' => true,
+        'one.two.three.third_leaf' => true,
+        'one.two.three.five.fifth_leaf' => true,
+        'one.two.three.five.eight' => 'fibonacci',
+        ];
+
+        $expected = [
+        'one' => [
+        'first_leaf' => true,
+        'two' => [
+                    'second_leaf' => true,
+                    'three' => [
+                        'third_leaf' => true,
+                        'five' => [
+                            'fifth_leaf' => true,
+                            'eight' => 'fibonacci'
+                        ]
+                    ]
+        ]
+        ],
+        ];
+
+        $this->assertSame($expected, Arr::undot($dotted));
+    }
+
+	 /**
+     * @test
+     */
+    public function it_expands_nested_arrays_with_numerical_keys()
+    {
+        $dotted = [
+			'first_array.0'  => 'bacon',
+			'first_array.1'  => 'ham',
+			'first_array.2'  => 'cheese',
+			'second_array.0' => 'bacon',
+			'second_array.1' => 'egg',
+			'second_array.2' => 'cheese',
+        ];
+
+        $expected = [
+			'first_array' => [
+				'bacon',
+				'ham',
+				'cheese',
+			],
+			'second_array' => [
+				'bacon',
+				'egg',
+				'cheese'
+			]
+		];
+
+        $this->assertSame($expected, Arr::undot($dotted));
+    }
+}