diff --git a/app/Http/Controllers/Api/V1/TaskController.php b/app/Http/Controllers/Api/V1/TaskController.php
index a83ac994..10106cf2 100644
--- a/app/Http/Controllers/Api/V1/TaskController.php
+++ b/app/Http/Controllers/Api/V1/TaskController.php
@@ -15,6 +15,7 @@ use App\Models\Task;
 use Illuminate\Auth\Access\AuthorizationException;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Resources\Json\JsonResource;
+use Illuminate\Support\Carbon;
 
 class TaskController extends Controller
 {
@@ -53,6 +54,12 @@ class TaskController extends Controller
         if (! $canViewAllTasks) {
             $query->visibleByEmployee($user);
         }
+        $doneFilter = $request->getFilterDone();
+        if ($doneFilter === 'true') {
+            $query->whereNotNull('done_at');
+        } elseif ($doneFilter === 'false') {
+            $query->whereNull('done_at');
+        }
 
         $tasks = $query->paginate(config('app.pagination_per_page_default'));
 
@@ -89,6 +96,9 @@ class TaskController extends Controller
     {
         $this->checkPermission($organization, 'tasks:update', $task);
         $task->name = $request->input('name');
+        if ($request->has('is_done')) {
+            $task->done_at = $request->getIsDone() ? Carbon::now() : null;
+        }
         $task->save();
 
         return new TaskResource($task);
diff --git a/app/Http/Requests/V1/Task/TaskIndexRequest.php b/app/Http/Requests/V1/Task/TaskIndexRequest.php
index 1da3d4b6..1b2afec4 100644
--- a/app/Http/Requests/V1/Task/TaskIndexRequest.php
+++ b/app/Http/Requests/V1/Task/TaskIndexRequest.php
@@ -39,6 +39,15 @@ class TaskIndexRequest extends FormRequest
                     return $builder;
                 }),
             ],
+            'done' => [
+                'string',
+                'in:true,false,all',
+            ],
         ];
     }
+
+    public function getFilterDone(): string
+    {
+        return $this->input('done', 'false');
+    }
 }
diff --git a/app/Http/Requests/V1/Task/TaskUpdateRequest.php b/app/Http/Requests/V1/Task/TaskUpdateRequest.php
index 3bc918c5..9f79e395 100644
--- a/app/Http/Requests/V1/Task/TaskUpdateRequest.php
+++ b/app/Http/Requests/V1/Task/TaskUpdateRequest.php
@@ -35,6 +35,16 @@ class TaskUpdateRequest extends FormRequest
                     return $builder->where('project_id', '=', $this->task->project_id);
                 }))->ignore($this->task->getKey())->withCustomTranslation('validation.task_name_already_exists'),
             ],
+            'is_done' => [
+                'boolean',
+            ],
         ];
     }
+
+    public function getIsDone(): bool
+    {
+        assert($this->has('is_done'));
+
+        return $this->boolean('is_done');
+    }
 }
diff --git a/app/Http/Resources/V1/Task/TaskResource.php b/app/Http/Resources/V1/Task/TaskResource.php
index 2a0ef0a2..c360a7e1 100644
--- a/app/Http/Resources/V1/Task/TaskResource.php
+++ b/app/Http/Resources/V1/Task/TaskResource.php
@@ -26,6 +26,8 @@ class TaskResource extends BaseResource
             'id' => $this->resource->id,
             /** @var string $name Name */
             'name' => $this->resource->name,
+            /** @var bool $is_done Whether the task is done */
+            'is_done' => $this->resource->is_done,
             /** @var string $project_id ID of the project */
             'project_id' => $this->resource->project_id,
             /** @var string $created_at When the tag was created */
diff --git a/app/Models/Task.php b/app/Models/Task.php
index c1cb1962..a322f117 100644
--- a/app/Models/Task.php
+++ b/app/Models/Task.php
@@ -7,6 +7,7 @@ namespace App\Models;
 use App\Models\Concerns\HasUuids;
 use Database\Factories\TaskFactory;
 use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Casts\Attribute;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
@@ -19,11 +20,13 @@ use Illuminate\Support\Carbon;
  * @property string $name
  * @property string $project_id
  * @property string $organization_id
+ * @property Carbon|null $done_at
  * @property Carbon|null $created_at
  * @property Carbon|null $updated_at
  * @property-read Project $project
  * @property-read Organization $organization
  * @property-read Collection<int, TimeEntry> $timeEntries
+ * @property-read bool $is_done
  *
  * @method static TaskFactory factory()
  */
@@ -76,4 +79,14 @@ class Task extends Model
             return $builder->visibleByEmployee($user);
         });
     }
+
+    /**
+     * @return Attribute<bool, never>
+     */
+    public function isDone(): Attribute
+    {
+        return Attribute::make(
+            get: fn (mixed $value, array $attributes) => isset($attributes['done_at']),
+        );
+    }
 }
diff --git a/database/factories/TaskFactory.php b/database/factories/TaskFactory.php
index 0921e9c4..b21e2f3c 100644
--- a/database/factories/TaskFactory.php
+++ b/database/factories/TaskFactory.php
@@ -25,6 +25,7 @@ class TaskFactory extends Factory
             'name' => $this->faker->word(),
             'project_id' => Project::factory(),
             'organization_id' => Organization::factory(),
+            'done_at' => null,
         ];
     }
 
@@ -37,6 +38,15 @@ class TaskFactory extends Factory
         });
     }
 
+    public function isDone(): self
+    {
+        return $this->state(function (array $attributes) {
+            return [
+                'done_at' => $this->faker->dateTime('now', 'UTC'),
+            ];
+        });
+    }
+
     public function forOrganization(Organization $organization): self
     {
         return $this->state(function (array $attributes) use ($organization) {
diff --git a/database/migrations/2024_06_24_114433_add_done_at_to_tasks_table.php b/database/migrations/2024_06_24_114433_add_done_at_to_tasks_table.php
new file mode 100644
index 00000000..3ed6849c
--- /dev/null
+++ b/database/migrations/2024_06_24_114433_add_done_at_to_tasks_table.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('tasks', function (Blueprint $table): void {
+            $table->dateTime('done_at')->nullable();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('tasks', function (Blueprint $table): void {
+            $table->dropColumn('done_at');
+        });
+    }
+};
diff --git a/tests/Unit/Endpoint/Api/V1/TaskEndpointTest.php b/tests/Unit/Endpoint/Api/V1/TaskEndpointTest.php
index f26f0273..a8076080 100644
--- a/tests/Unit/Endpoint/Api/V1/TaskEndpointTest.php
+++ b/tests/Unit/Endpoint/Api/V1/TaskEndpointTest.php
@@ -9,6 +9,7 @@ use App\Models\Project;
 use App\Models\ProjectMember;
 use App\Models\Task;
 use App\Models\TimeEntry;
+use Illuminate\Support\Carbon;
 use Laravel\Passport\Passport;
 use PHPUnit\Framework\Attributes\UsesClass;
 
@@ -76,6 +77,85 @@ class TaskEndpointTest extends ApiEndpointTestAbstract
         $response->assertJsonCount(4, 'data');
     }
 
+    public function test_index_endpoint_without_filter_done_returns_list_of_all_tasks_of_organization(): void
+    {
+        // Arrange
+        $data = $this->createUserWithPermission([
+            'tasks:view',
+            'tasks:view:all',
+        ]);
+        $notDoneTasks = Task::factory()->forOrganization($data->organization)->createMany(2);
+        $doneTasks = Task::factory()->forOrganization($data->organization)->isDone()->createMany(2);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.tasks.index', [$data->organization->getKey()]));
+
+        // Assert
+        $response->assertStatus(200);
+        $response->assertJsonCount(2, 'data');
+        $this->assertEqualsCanonicalizing($notDoneTasks->pluck('id')->toArray(), $response->json('data.*.id'));
+    }
+
+    public function test_index_endpoint_with_filter_done_true_returns_list_of_all_done_tasks_of_organization(): void
+    {
+        // Arrange
+        $data = $this->createUserWithPermission([
+            'tasks:view',
+            'tasks:view:all',
+        ]);
+        $notDoneTasks = Task::factory()->forOrganization($data->organization)->createMany(2);
+        $doneTasks = Task::factory()->forOrganization($data->organization)->isDone()->createMany(2);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.tasks.index', [$data->organization->getKey(), 'done' => 'true']));
+
+        // Assert
+        $response->assertStatus(200);
+        $response->assertJsonCount(2, 'data');
+        $this->assertEqualsCanonicalizing($doneTasks->pluck('id')->toArray(), $response->json('data.*.id'));
+    }
+
+    public function test_index_endpoint_with_filter_done_false_returns_list_of_all_not_done_tasks_of_organization(): void
+    {
+        // Arrange
+        $data = $this->createUserWithPermission([
+            'tasks:view',
+            'tasks:view:all',
+        ]);
+        $notDoneTasks = Task::factory()->forOrganization($data->organization)->createMany(2);
+        $doneTasks = Task::factory()->forOrganization($data->organization)->isDone()->createMany(2);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.tasks.index', [$data->organization->getKey(), 'done' => 'false']));
+
+        // Assert
+        $response->assertStatus(200);
+        $response->assertJsonCount(2, 'data');
+        $this->assertEqualsCanonicalizing($notDoneTasks->pluck('id')->toArray(), $response->json('data.*.id'));
+    }
+
+    public function test_index_endpoint_with_filter_done_all_returns_list_of_all_tasks_of_organization(): void
+    {
+        // Arrange
+        $data = $this->createUserWithPermission([
+            'tasks:view',
+            'tasks:view:all',
+        ]);
+        $notDoneTasks = Task::factory()->forOrganization($data->organization)->createMany(2);
+        $doneTasks = Task::factory()->forOrganization($data->organization)->isDone()->createMany(2);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.tasks.index', [$data->organization->getKey(), 'done' => 'all']));
+
+        // Assert
+        $response->assertStatus(200);
+        $response->assertJsonCount(4, 'data');
+    }
+
     public function test_index_endpoint_returns_list_of_all_tasks_with_access_of_organization_if_user_has_no_all_permission(): void
     {
         // Arrange
@@ -395,6 +475,54 @@ class TaskEndpointTest extends ApiEndpointTestAbstract
         ]);
     }
 
+    public function test_update_endpoint_can_set_task_to_done(): void
+    {
+        // Arrange
+        $now = Carbon::now();
+        $this->travelTo($now);
+        $data = $this->createUserWithPermission([
+            'tasks:update',
+        ]);
+        $task = Task::factory()->forOrganization($data->organization)->create();
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->putJson(route('api.v1.tasks.update', [$data->organization->getKey(), $task->getKey()]), [
+            'name' => $task->name,
+            'is_done' => true,
+        ]);
+
+        // Assert
+        $response->assertStatus(200);
+        $this->assertDatabaseHas(Task::class, [
+            'id' => $task->getKey(),
+            'done_at' => $now->toDateTimeString(),
+        ]);
+    }
+
+    public function test_update_endpoint_can_set_task_to_not_done(): void
+    {
+        // Arrange
+        $data = $this->createUserWithPermission([
+            'tasks:update',
+        ]);
+        $task = Task::factory()->forOrganization($data->organization)->isDone()->create();
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->putJson(route('api.v1.tasks.update', [$data->organization->getKey(), $task->getKey()]), [
+            'name' => $task->name,
+            'is_done' => false,
+        ]);
+
+        // Assert
+        $response->assertStatus(200);
+        $this->assertDatabaseHas(Task::class, [
+            'id' => $task->getKey(),
+            'done_at' => null,
+        ]);
+    }
+
     public function test_delete_endpoint_deletes_tasks_if_user_has_permission(): void
     {
         // Arrange
diff --git a/tests/Unit/Model/TaskModelTest.php b/tests/Unit/Model/TaskModelTest.php
index e86b8027..144f3718 100644
--- a/tests/Unit/Model/TaskModelTest.php
+++ b/tests/Unit/Model/TaskModelTest.php
@@ -90,4 +90,28 @@ class TaskModelTest extends ModelTestAbstract
             $taskPrivateButMember->getKey(),
         ], $allTasks);
     }
+
+    public function test_accessor_is_done_is_true_if_done_at_is_not_null(): void
+    {
+        // Arrange
+        $task = Task::factory()->isDone()->create();
+
+        // Act
+        $task->refresh();
+
+        // Assert
+        $this->assertTrue($task->is_done);
+    }
+
+    public function test_accessor_is_done_is_false_if_done_at_is_null(): void
+    {
+        // Arrange
+        $task = Task::factory()->create();
+
+        // Act
+        $task->refresh();
+
+        // Assert
+        $this->assertFalse($task->is_done);
+    }
 }