diff --git a/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesCommand.php b/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesCommand.php
index 18974c6..062e5ea 100644
--- a/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesCommand.php
+++ b/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesCommand.php
@@ -12,6 +12,9 @@ class SetParticipationFeesCommand {
 
     public function execute() : SetParticipationFeesResponse {
         $response = new SetParticipationFeesResponse();
+        $this->request->event->sibling_reduction = $this->request->siblingReduction;
+        $this->request->event->save();
+
         $this->cleanBefore();
 
         $this->request->event->participationFee1()->associate(EventParticipationFee::create([
diff --git a/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesRequest.php b/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesRequest.php
index 28f2ec4..0df1171 100644
--- a/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesRequest.php
+++ b/app/Domains/Event/Actions/SetParticipationFees/SetParticipationFeesRequest.php
@@ -12,13 +12,16 @@ class SetParticipationFeesRequest {
     public ?array $participationFeeThird;
     public ?array $participationFeeFourth;
 
+    public bool $siblingReduction;
 
-    public function __construct(Event $event, array $participationFeeFirst) {
+
+    public function __construct(Event $event, array $participationFeeFirst, bool $siblingReduction) {
         $this->event = $event;
         $this->participationFeeFirst = $participationFeeFirst;
         $this->participationFeeSecond = null;
         $this->participationFeeThird = null;
         $this->participationFeeFourth = null;
+        $this->siblingReduction = $siblingReduction;
     }
 
 }
diff --git a/app/Domains/Event/Controllers/DetailsController.php b/app/Domains/Event/Controllers/DetailsController.php
index fbfac37..b0d7ebc 100644
--- a/app/Domains/Event/Controllers/DetailsController.php
+++ b/app/Domains/Event/Controllers/DetailsController.php
@@ -87,7 +87,8 @@ class DetailsController extends CommonController {
             'amount_solidarity' => null !== $request->input('pft_1_amount_solidarity') ? Amount::fromString($request->input('pft_1_amount_solidarity')) : null
         ];
 
-        $participationFeeRequest = new SetParticipationFeesRequest($event, $participationFeeFirst);
+        $siblingReduction = $request->input('sibling_reduction') ?? false;
+        $participationFeeRequest = new SetParticipationFeesRequest($event, $participationFeeFirst, $siblingReduction);
 
         if ($request->input('pft_2_active')) {
             $participationFeeRequest->participationFeeSecond = [
diff --git a/app/Domains/Event/Controllers/SignupController.php b/app/Domains/Event/Controllers/SignupController.php
index c6999eb..67cc0b6 100644
--- a/app/Domains/Event/Controllers/SignupController.php
+++ b/app/Domains/Event/Controllers/SignupController.php
@@ -70,6 +70,8 @@ class SignupController extends CommonController {
         $event = $this->events->getById($eventId, false);
         $eventResource = $event->toResource();
         $registrationData = $request->input('registration_data');
+        $siblingReduction = $registrationData['sibling'] === 'true';
+
 
         $arrival = \DateTime::createFromFormat('Y-m-d', $registrationData['arrival']);
         $departure = \DateTime::createFromFormat('Y-m-d', $registrationData['departure']);
@@ -81,16 +83,17 @@ class SignupController extends CommonController {
             $registrationData['nachname'],
             $registrationData['email_1'],
             DateTime::createFromFormat('Y-m-d', $registrationData['geburtsdatum']));
-/*
+
             if ($doubleCheckEventRegistrationProvider->isRegistered()) {
                 return response()->json(['status' => 'exists']);
-            }*/
+            }
 
         $amount = $eventResource->calculateAmount(
             $registrationData['participationType'],
             $registrationData['beitrag'],
             $arrival,
-            $departure
+            $departure,
+            $siblingReduction
         );
 
         $signupRequest = new SignUpRequest(
@@ -164,12 +167,15 @@ class SignupController extends CommonController {
     public function calculateAmount(int $eventId, Request $request, bool $forDisplay = true) : JsonResponse | float {
         $event = $this->events->getById($eventId, false)->toResource();
 
+        $siblingReduction = $request->input('sibling') === 'true';
+
         return response()->json(['amount' =>
             $event->calculateAmount(
                 $request->input('participationType'),
                 $request->input('beitrag'),
                 \DateTime::createFromFormat('Y-m-d', $request->input('arrival')),
-                \DateTime::createFromFormat('Y-m-d', $request->input('departure'))
+                \DateTime::createFromFormat('Y-m-d', $request->input('departure')),
+                $siblingReduction
             )->toString()
         ]);
     }
diff --git a/app/Domains/Event/Views/Partials/ParticipationFees.vue b/app/Domains/Event/Views/Partials/ParticipationFees.vue
index 53e687c..7e1f1da 100644
--- a/app/Domains/Event/Views/Partials/ParticipationFees.vue
+++ b/app/Domains/Event/Views/Partials/ParticipationFees.vue
@@ -38,9 +38,12 @@
         "pft_4_description": props.event.participationFee_4.description,
 
         'maxAmount': props.event.maxAmount,
+        'sibling_reduction': props.event.siblingReduction,
 
     })
 
+    console.log(formData)
+
     function validateInput() {
         var noErrors = true;
 
@@ -103,6 +106,7 @@
                 pft_4_description: formData.pft_4_description,
 
                 maxAmount: formData.maxAmount,
+                sibling_reduction: formData.sibling_reduction,
             }
         })
 
@@ -277,7 +281,14 @@
         </tr>
 
         <tr>
-            <td colspan="4">
+            <td colspan="2">
+                <input type="checkbox" v-model="formData.sibling_reduction" id="sibling_reduction" :checked="formData.sibling_reduction" />
+                <label for="sibling_reduction">50% Preisnachlass für Geschwisterkinder gewähren</label>
+            </td>
+        </tr>
+
+        <tr>
+            <td colspan="4" style="padding-top: 20px;">
                 <input type="button" value="Speichern" @click="saveParticipationFees" />
             </td>
         </tr>
diff --git a/app/Domains/Event/Views/Partials/SignUpForm/composables/useSignupForm.js b/app/Domains/Event/Views/Partials/SignUpForm/composables/useSignupForm.js
index 40c4905..e5b50a1 100644
--- a/app/Domains/Event/Views/Partials/SignUpForm/composables/useSignupForm.js
+++ b/app/Domains/Event/Views/Partials/SignUpForm/composables/useSignupForm.js
@@ -30,6 +30,7 @@ console.log(participantData)
         telefon_2: '',
         email_2: '',
         badeerlaubnis: '-1',
+        sibling: '-1',
         first_aid: '-1',
         participant_group: '',
         beitrag: 'regular',
@@ -66,6 +67,7 @@ console.log(participantData)
                     addons: selectedAddons,
                     participationType: formData.participationType,
                     beitrag: formData.beitrag,
+                    sibling: formData.sibling,
                 })
                summaryAmount.value = res.data.amount
             } finally {
diff --git a/app/Domains/Event/Views/Partials/SignUpForm/steps/StepContactPerson.vue b/app/Domains/Event/Views/Partials/SignUpForm/steps/StepContactPerson.vue
index dd8c8b8..5b6367c 100644
--- a/app/Domains/Event/Views/Partials/SignUpForm/steps/StepContactPerson.vue
+++ b/app/Domains/Event/Views/Partials/SignUpForm/steps/StepContactPerson.vue
@@ -27,6 +27,11 @@ const next = () => {
         hasError = true
     }
 
+    if (props.event.siblingReduction && props.formData.sibling === '-1') {
+        errors.sibling = 'Bitte eine Entscheidung treffen.'
+    }
+
+
     if (!props.formData.telefon_2) {
         errors.telefon_2 = 'Bitte eine Telefonnummer angeben.'
         hasError = true
@@ -110,6 +115,20 @@ const next = () => {
                     <ErrorText :message="errors.first_aid" />
                 </td>
             </tr>
+            <tr v-if="event.siblingReduction">
+                <td>Ist bereits ein vollzahlendes Geschwisterkind für die Veranstaltung angemeldet:*</td>
+                <td>
+                    <select v-model="formData.sibling">
+                        <option value="-1">Bitte wählen</option>
+                        <option value="true">Ja</option>
+                        <option value="false">Nein</option>
+                    </select><br />
+                    <span style="font-size: 0.8rem; color: #6b7280;">
+                        Ist bereits ein vollzahlendes Geschwisterkind angemeldet, reduziert sich der Teilnahmebeitrag um 50%. Der Preisnachlass wird am Ende der Anmeldung automatisch abgezogen.
+                    </span>
+                    <ErrorText :message="errors.sibling" />
+                </td>
+            </tr>
             <tr>
                 <td></td>
                 <td>
diff --git a/app/Domains/Event/Views/Partials/SignUpForm/steps/StepRegistrationMode.vue b/app/Domains/Event/Views/Partials/SignUpForm/steps/StepRegistrationMode.vue
index b640e44..a57ce47 100644
--- a/app/Domains/Event/Views/Partials/SignUpForm/steps/StepRegistrationMode.vue
+++ b/app/Domains/Event/Views/Partials/SignUpForm/steps/StepRegistrationMode.vue
@@ -20,6 +20,7 @@ const nextStep = () => {
     const hasAddons = (props.event.addons?.length ?? 0) > 0
     emit('next', hasAddons ? 6 : 7)
 }
+console.log(props.formData, props.event)
 </script>
 
 <template>
@@ -113,6 +114,9 @@ const nextStep = () => {
                 </td>
             </tr>
         </table>
+        <p v-if="props.event.siblingReduction && props.formData.sibling === 'true'">
+            Der Preisnachlass in Höhe von 50% wird am Ende des Anmeldeprozesses berechnet.
+        </p>
 
         <div class="btn-row">
             <button type="button" class="btn-secondary" @click="emit('back', 3)">← Zurück</button>
diff --git a/app/Models/Event.php b/app/Models/Event.php
index 8a6e6a2..9e9421a 100644
--- a/app/Models/Event.php
+++ b/app/Models/Event.php
@@ -37,6 +37,7 @@ use Illuminate\Http\Resources\Json\JsonResource;
  * @property string $registration_link
  * @property boolean $pay_per_day
  * @property boolean $pay_direct
+ * @property boolean $sibling_reduction
  * @property boolean $send_weekly_report
  * @property int $participation_fee_1
  * @property int $participation_fee_2
@@ -73,6 +74,7 @@ class Event extends InstancedModel
         'registration_link',
         'pay_per_day',
         'pay_direct',
+        'sibling_reduction',
         'send_weekly_report',
         'participation_fee_1',
         'participation_fee_2',
@@ -104,6 +106,8 @@ class Event extends InstancedModel
         'support_per_person' => AmountCast::class,
         'support_flat' => AmountCast::class,
         'total_max_amount' => AmountCast::class,
+
+        'sibling_reduction' => 'boolean',
     ];
 
     public function tenant(): BelongsTo
diff --git a/app/Resources/EventResource.php b/app/Resources/EventResource.php
index 89e7f12..81519a0 100644
--- a/app/Resources/EventResource.php
+++ b/app/Resources/EventResource.php
@@ -74,6 +74,7 @@ class EventResource extends JsonResource{
             $returnArray['nameShort'] = substr($returnArray['nameShort'], 8, 13) . '...';
         }
 
+        $returnArray['siblingReduction'] = $this->event->sibling_reduction ?? true;
         $returnArray['costUnit'] = new CostUnitResource($this->event->costUnit()->first())->toArray(true);
         $returnArray['solidarityPayment'] = $this->event->participation_fee_type === ParticipationFeeType::PARTICIPATION_FEE_TYPE_SOLIDARITY;
         $returnArray['payPerDay'] = $this->event->pay_per_day;
@@ -301,7 +302,8 @@ class EventResource extends JsonResource{
         string $participationType,
         string $feeType,
         DateTime $arrival,
-        DateTime $departure
+        DateTime $departure,
+        bool $hasSibling
     ) : Amount {
         $fee = collect([
             $this->event->participationFee1,
@@ -324,6 +326,10 @@ class EventResource extends JsonResource{
             $basicFee = $basicFee->multiply($days);
         }
 
+        if ($hasSibling && $this->event->sibling_reduction) {
+            $basicFee = $basicFee->multiply(0.5);
+        }
+
         return $basicFee;
     }
 }
diff --git a/database/migrations/2026_02_14_140010_create_events.php b/database/migrations/2026_02_14_140010_create_events.php
index a38b9be..3963b53 100644
--- a/database/migrations/2026_02_14_140010_create_events.php
+++ b/database/migrations/2026_02_14_140010_create_events.php
@@ -59,6 +59,7 @@ return new class extends Migration {
             $table->string('registration_link')->nullable();
             $table->boolean('pay_per_day');
             $table->boolean('pay_direct');
+            $table->boolean('sibling_reduction')->default(false);
             $table->boolean('send_weekly_report')->default(true);
             $table->foreignId('participation_fee_1')->nullable()->constrained('event_participation_fees', 'id')->nullOnDelete()->cascadeOnUpdate();
             $table->foreignId('participation_fee_2')->nullable()->constrained('event_participation_fees', 'id')->nullOnDelete()->cascadeOnUpdate();