diff --git a/app/Models/User.php b/app/Models/User.php
index 085bb8f76..3b4aa20a9 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -12,13 +12,17 @@
 use App\Enums\RemotesFrom;
 use Carbon\CarbonInterface;
 use Database\Factories\UserFactory;
+use Illuminate\Contracts\Database\Eloquent\Builder as BuilderContract;
 use Illuminate\Database\Eloquent\Attributes\Hidden;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\HasOne;
+use Illuminate\Database\Eloquent\Relations\Relation;
 use Illuminate\Database\Query\Builder as QueryBuilder;
 use Illuminate\Foundation\Auth\User as Authenticatable;
 use Illuminate\Support\Facades\DB;
@@ -370,6 +374,20 @@ public function isOnboarded(): bool
         return $this->onboarded_at !== null;
     }
 
+    /**
+     * GitHub usernames are unique case-insensitively, so `/@NunoMaduro` finds `nunomaduro` like github.com does.
+     *
+     * @param  Model|Builder<User>|Relation<User, Model, mixed>  $query
+     */
+    public function resolveRouteBindingQuery(mixed $query, mixed $value, mixed $field = null): BuilderContract
+    {
+        if ($field === 'username' && is_string($value)) {
+            return $query->whereRaw('LOWER(username) = ?', [mb_strtolower($value)]);
+        }
+
+        return parent::resolveRouteBindingQuery($query, $value, $field);
+    }
+
     public function isAdmin(): bool
     {
         /** @var list<string> $admins */
diff --git a/tests/Feature/Controllers/Api/UserControllerTest.php b/tests/Feature/Controllers/Api/UserControllerTest.php
index 5212ea033..f56e73321 100644
--- a/tests/Feature/Controllers/Api/UserControllerTest.php
+++ b/tests/Feature/Controllers/Api/UserControllerTest.php
@@ -72,6 +72,14 @@
     $this->getJson('/api/v1/users/missing')->assertNotFound();
 });
 
+it('finds a username in any case, like github', function (): void {
+    User::factory()->create(['username' => 'NunoMaduro']);
+
+    $this->getJson('/api/v1/users/nunomaduro')
+        ->assertOk()
+        ->assertJsonPath('data.username', 'NunoMaduro');
+});
+
 it('shows a signed request the profile as the web shows it to its user', function (): void {
     $this->travelTo(now()->setDate(2026, 10, 15)->setTime(12, 0));
 
diff --git a/tests/Feature/Controllers/UserControllerTest.php b/tests/Feature/Controllers/UserControllerTest.php
index f98d5895f..eb39f4fab 100644
--- a/tests/Feature/Controllers/UserControllerTest.php
+++ b/tests/Feature/Controllers/UserControllerTest.php
@@ -322,6 +322,23 @@
     $response->assertNotFound();
 });
 
+it('finds the profile and commits of a username in any case, like github', function (): void {
+    $user = User::factory()->create(['username' => 'NunoMaduro']);
+    $commit = Commit::factory()->for($user)->create();
+    $viewer = User::factory()->create();
+
+    foreach (['/@nunomaduro', '/@NUNOMADURO', '/@NunoMaduro'] as $url) {
+        $this->actingAs($viewer)
+            ->get($url)
+            ->assertOk()
+            ->assertInertia(fn (AssertableInertia $page): AssertableInertia => $page->where('user.username', 'NunoMaduro'));
+    }
+
+    $this->actingAs($viewer)
+        ->get('/@nunomaduro/commits/'.$commit->id)
+        ->assertOk();
+});
+
 it('shows guests the profile with its approved commits and a link preview', function (): void {
     $user = User::factory()->create([
         'username' => 'octocat',