diff --git a/src/Phaseolies/Support/Collection.php b/src/Phaseolies/Support/Collection.php
index d59e10a..9134b09 100644
--- a/src/Phaseolies/Support/Collection.php
+++ b/src/Phaseolies/Support/Collection.php
@@ -761,4 +761,57 @@ public function partition(callable $callback): array
             new static($this->model, $failed)
         ];
     }
+
+    /**
+     * Get items not present in the given items.
+     *
+     * @param mixed $items
+     * @return static
+     */
+    public function diff($items): self
+    {
+        $compare = $items instanceof self ? $items->all() : (array) $items;
+
+        $result = [];
+        foreach ($this->data as $item) {
+            if (!in_array($item, $compare, true)) {
+                $result[] = $item;
+            }
+        }
+
+        return new static($this->model, $result);
+    }
+
+    /**
+     * Get items present in both this collection and given items
+     *
+     * @param mixed $items
+     * @return static
+     */
+    public function intersect($items): self
+    {
+        $compare = $items instanceof self ? $items->all() : (array) $items;
+
+        $result = [];
+        foreach ($this->data as $item) {
+            if (in_array($item, $compare, true)) {
+                $result[] = $item;
+            }
+        }
+
+        return new static($this->model, $result);
+    }
+
+    /**
+     * Execute a callback over the collection without modifying it.
+     *
+     * @param callable $callback
+     * @return $this
+     */
+    public function tap(callable $callback): self
+    {
+        $callback($this);
+
+        return $this;
+    }
 }
diff --git a/tests/CollectionTest.php b/tests/CollectionTest.php
index 4c1cdab..b46519c 100644
--- a/tests/CollectionTest.php
+++ b/tests/CollectionTest.php
@@ -1315,4 +1315,61 @@ public function testPartitionWithObjects()
         $this->assertCount(2, $active);
         $this->assertCount(1, $inactive);
     }
+
+    public function testDiffReturnsItemsNotInOtherCollection()
+    {
+        $modelClass = get_class($this->makeTestModel(0, ""));
+        $collection1 = new Collection($modelClass, [1, 2, 3, 4, 5]);
+        $collection2 = new Collection($modelClass, [3, 4, 5, 6, 7]);
+
+        $diff = $collection1->diff($collection2);
+
+        $this->assertEquals([1, 2], $diff->all());
+    }
+
+    public function testDiffWithArray()
+    {
+        $modelClass = get_class($this->makeTestModel(0, ""));
+        $collection = new Collection($modelClass, [1, 2, 3, 4, 5]);
+
+        $diff = $collection->diff([3, 4, 5]);
+
+        $this->assertEquals([1, 2], $diff->all());
+    }
+
+    public function testIntersectReturnsCommonItems()
+    {
+        $modelClass = get_class($this->makeTestModel(0, ""));
+        $collection1 = new Collection($modelClass, [1, 2, 3, 4, 5]);
+        $collection2 = new Collection($modelClass, [3, 4, 5, 6, 7]);
+
+        $intersect = $collection1->intersect($collection2);
+
+        $this->assertEquals([3, 4, 5], $intersect->all());
+    }
+
+    public function testIntersectWithArray()
+    {
+        $modelClass = get_class($this->makeTestModel(0, ""));
+        $collection = new Collection($modelClass, [1, 2, 3, 4, 5]);
+
+        $intersect = $collection->intersect([2, 3, 6]);
+
+        $this->assertEquals([2, 3], $intersect->all());
+    }
+
+    public function testTapExecutesCallbackWithoutModifying()
+    {
+        $modelClass = get_class($this->makeTestModel(0, ""));
+        $collection = new Collection($modelClass, [1, 2, 3]);
+
+        $tapped = null;
+        $result = $collection->tap(function ($col) use (&$tapped) {
+            $tapped = $col->count();
+        });
+
+        $this->assertEquals(3, $tapped);
+        $this->assertSame($collection, $result);
+        $this->assertEquals([1, 2, 3], $collection->all());
+    }
 }