diff --git a/.github/scripts/check-idor-model-coverage.py b/.github/scripts/check-idor-model-coverage.py
index aa7d0b87aa9c..a025b761894d 100644
--- a/.github/scripts/check-idor-model-coverage.py
+++ b/.github/scripts/check-idor-model-coverage.py
@@ -355,6 +355,7 @@ def get_scoped_models() -> tuple[dict[str, set[str]], set[str], set[str], set[st
         "RoleMembership",
         "LinkedIdentityProviderConfig",
         "IdJagIdentity",
+        "SandboxSenderOrganizationBlock",
         # --- User-scoped (cross-tenant by design) ---
         "NotificationViewed",
         "SCIMProvisionedUser",
diff --git a/.semgrep/rules/security/idor-team-scoped-models.yaml b/.semgrep/rules/security/idor-team-scoped-models.yaml
index 212b0afc496e..0502e7516442 100644
--- a/.semgrep/rules/security/idor-team-scoped-models.yaml
+++ b/.semgrep/rules/security/idor-team-scoped-models.yaml
@@ -1376,6 +1376,7 @@ rules:
                               |Role
                               |RoleExternalReference
                               |RoleMembership
+                              |SandboxSenderOrganizationBlock
                           )$
                 - focus-metavariable: $SINK
       pattern-sanitizers:
@@ -1459,6 +1460,7 @@ rules:
                         |Role
                         |RoleExternalReference
                         |RoleMembership
+                        |SandboxSenderOrganizationBlock
                     )$
           - pattern-not: $M.objects. ... .$METHOD2(..., organization=$O, ...)
           - pattern-not: $M.objects. ... .$METHOD2(..., organization_id=$O, ...)
diff --git a/docs/internal/workflows-email-sending-tiers.md b/docs/internal/workflows-email-sending-tiers.md
index 865e62487730..6db1b6190e27 100644
--- a/docs/internal/workflows-email-sending-tiers.md
+++ b/docs/internal/workflows-email-sending-tiers.md
@@ -28,6 +28,8 @@ Only workflows that send email are subject to the tiers; SMS, push, and webhook
 
 The `workflows-sandbox-sender` flag enables a PostHog-managed email integration per project through `POST /api/projects/:project_id/integrations/email_sandbox_sender/`.
 The endpoint requires `integration:write` and project membership. Repeated requests keep the same integration and refresh its display name from the organization name.
+Staff turn the sandbox sender off for one organization by adding a `SandboxSenderOrganizationBlock` row in the Django admin, and lift the block by deleting the row.
+While the block exists, the endpoint returns 404 for the organization's projects. Existing sandbox senders stay, and the email worker does not read the block.
 Set `WORKFLOWS_SANDBOX_SENDER_DOMAIN`, `SES_SANDBOX_FROM_ADDRESS`, and `SES_SANDBOX_TENANT_NAME` in Django; any empty value leaves the endpoint unavailable.
 The worker sends from the same `SES_SANDBOX_FROM_ADDRESS`, so set it once for Django and the worker. The address the UI shows is then the address the worker sends from.
 Workflow email steps and test sends offer it as a sender.
diff --git a/products/workflows/backend/admin/__init__.py b/products/workflows/backend/admin/__init__.py
index 9e90819008f7..dae51551b034 100644
--- a/products/workflows/backend/admin/__init__.py
+++ b/products/workflows/backend/admin/__init__.py
@@ -4,5 +4,6 @@
     hog_flow_admin,
     hog_flow_batch_job_admin,
     hog_flow_template_admin,
+    sandbox_sender_organization_block_admin,
     team_workflows_config_admin,
 )
diff --git a/products/workflows/backend/admin/sandbox_sender_organization_block_admin.py b/products/workflows/backend/admin/sandbox_sender_organization_block_admin.py
new file mode 100644
index 000000000000..6c5e0792b146
--- /dev/null
+++ b/products/workflows/backend/admin/sandbox_sender_organization_block_admin.py
@@ -0,0 +1,31 @@
+from typing import cast
+
+from django.contrib import admin
+from django.forms import ModelForm
+from django.http import HttpRequest
+
+from posthog.models.user import User
+
+from products.workflows.backend.models import SandboxSenderOrganizationBlock
+
+
+@admin.register(SandboxSenderOrganizationBlock)
+class SandboxSenderOrganizationBlockAdmin(admin.ModelAdmin):
+    list_display = ("organization", "reason", "created_by", "created_at")
+    fields = ("organization", "reason", "created_by", "created_at")
+    readonly_fields = ("created_by", "created_at")
+    raw_id_fields = ("organization",)
+    search_fields = ("organization__id", "organization__name", "reason")
+    list_select_related = ("organization", "created_by")
+    ordering = ("-created_at",)
+
+    def save_model(
+        self,
+        request: HttpRequest,
+        obj: SandboxSenderOrganizationBlock,
+        form: ModelForm | None,
+        change: bool,
+    ) -> None:
+        if not change:
+            obj.created_by = cast(User, request.user)
+        super().save_model(request, obj, form, change)
diff --git a/products/workflows/backend/migrations/0040_sandbox_sender_organization_block.py b/products/workflows/backend/migrations/0040_sandbox_sender_organization_block.py
new file mode 100644
index 000000000000..aa63af505d18
--- /dev/null
+++ b/products/workflows/backend/migrations/0040_sandbox_sender_organization_block.py
@@ -0,0 +1,52 @@
+# Generated by Django 5.2.18 on 2026-10-26 06:46
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("posthog", "1411_personalapikey_expires_at"),
+        ("workflows", "0039_sandbox_sender_tenant_state"),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="SandboxSenderOrganizationBlock",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("reason", models.TextField()),
+                ("created_at", models.DateTimeField(auto_now_add=True)),
+                (
+                    "created_by",
+                    models.ForeignKey(
+                        blank=True,
+                        db_constraint=False,
+                        null=True,
+                        on_delete=django.db.models.deletion.SET_NULL,
+                        related_name="+",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+                (
+                    "organization",
+                    models.OneToOneField(
+                        db_constraint=False,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="+",
+                        to="posthog.organization",
+                    ),
+                ),
+            ],
+        ),
+    ]
diff --git a/products/workflows/backend/migrations/max_migration.txt b/products/workflows/backend/migrations/max_migration.txt
index c3daea1fde11..c2673e4f68d4 100644
--- a/products/workflows/backend/migrations/max_migration.txt
+++ b/products/workflows/backend/migrations/max_migration.txt
@@ -1 +1 @@
-0039_sandbox_sender_tenant_state
+0040_sandbox_sender_organization_block
diff --git a/products/workflows/backend/models/__init__.py b/products/workflows/backend/models/__init__.py
index fdf755e421f6..1b310b9e4de3 100644
--- a/products/workflows/backend/models/__init__.py
+++ b/products/workflows/backend/models/__init__.py
@@ -4,6 +4,7 @@
 from .hog_flow_optimization import HogFlowOptimization
 from .hog_flow_revision import HogFlowRevision
 from .hog_flow_schedule.hog_flow_schedule import HogFlowSchedule
+from .sandbox_sender_organization_block import SandboxSenderOrganizationBlock
 from .sandbox_sender_tenant_state import SandboxSenderTenantState
 from .team_workflows_config import TeamWorkflowsConfig
 from .workflow_idea import WorkflowIdea
@@ -16,6 +17,7 @@
     "HogFlowRevision",
     "HogFlowSchedule",
     "HogFlowTemplate",
+    "SandboxSenderOrganizationBlock",
     "SandboxSenderTenantState",
     "TeamWorkflowsConfig",
     "WorkflowIdea",
diff --git a/products/workflows/backend/models/sandbox_sender_organization_block.py b/products/workflows/backend/models/sandbox_sender_organization_block.py
new file mode 100644
index 000000000000..6e579d32d197
--- /dev/null
+++ b/products/workflows/backend/models/sandbox_sender_organization_block.py
@@ -0,0 +1,15 @@
+from django.db import models
+
+
+class SandboxSenderOrganizationBlock(models.Model):
+    organization = models.OneToOneField(
+        "posthog.Organization", on_delete=models.CASCADE, db_constraint=False, related_name="+"
+    )
+    reason = models.TextField()
+    created_by = models.ForeignKey(
+        "posthog.User", on_delete=models.SET_NULL, null=True, blank=True, db_constraint=False, related_name="+"
+    )
+    created_at = models.DateTimeField(auto_now_add=True)
+
+    def __str__(self) -> str:
+        return self.organization.name
diff --git a/products/workflows/backend/services/sandbox_sender.py b/products/workflows/backend/services/sandbox_sender.py
index 2da94cd73d1f..2828edb454e5 100644
--- a/products/workflows/backend/services/sandbox_sender.py
+++ b/products/workflows/backend/services/sandbox_sender.py
@@ -8,6 +8,7 @@
 from posthog.plugins.plugin_server_api import reload_integrations_on_workers
 
 from products.workflows.backend.facade.contracts import SandboxEmailSender, SandboxSenderUnavailable
+from products.workflows.backend.models.sandbox_sender_organization_block import SandboxSenderOrganizationBlock
 
 logger = structlog.get_logger(__name__)
 
@@ -54,9 +55,13 @@ def _sandbox_sender_enabled(team: Team) -> bool:
         return False
 
 
+def _organization_blocked(team: Team) -> bool:
+    return SandboxSenderOrganizationBlock.objects.filter(organization_id=team.organization_id).exists()
+
+
 def ensure_sandbox_email_sender(team_id: int) -> SandboxEmailSender:
     team = Team.objects.select_related("organization").get(id=team_id)
-    if not _sandbox_sender_configured() or not _sandbox_sender_enabled(team):
+    if not _sandbox_sender_configured() or not _sandbox_sender_enabled(team) or _organization_blocked(team):
         raise SandboxSenderUnavailable()
 
     config = _sandbox_sender_config(team.organization.name)
diff --git a/products/workflows/backend/test/test_sandbox_sender_organization_block_admin.py b/products/workflows/backend/test/test_sandbox_sender_organization_block_admin.py
new file mode 100644
index 000000000000..46946a4e78c4
--- /dev/null
+++ b/products/workflows/backend/test/test_sandbox_sender_organization_block_admin.py
@@ -0,0 +1,36 @@
+from posthog.test.base import BaseTest
+
+from django.test import Client, override_settings
+
+from products.workflows.backend.models import SandboxSenderOrganizationBlock
+
+ADMIN_URL = "/admin/workflows/sandboxsenderorganizationblock/"
+
+
+@override_settings(STORAGES={"staticfiles": {"BACKEND": "django.contrib.staticfiles.storage.StaticFilesStorage"}})
+class TestSandboxSenderOrganizationBlockAdmin(BaseTest):
+    def setUp(self) -> None:
+        super().setUp()
+        self.user.is_staff = True
+        self.user.save()
+        self.organization.name = "Blocked example organization"
+        self.organization.save()
+        self.client = Client()
+        self.client.force_login(self.user)
+
+    def test_staff_add_a_block_with_its_author_and_delete_it(self) -> None:
+        added = self.client.post(
+            f"{ADMIN_URL}add/", data={"organization": str(self.organization.id), "reason": "Abuse report"}
+        )
+
+        assert added.status_code == 302, added.content
+        block = SandboxSenderOrganizationBlock.objects.get(organization=self.organization)
+        assert (block.reason, block.created_by) == ("Abuse report", self.user)
+
+        confirmation = self.client.get(f"{ADMIN_URL}{block.pk}/delete/")
+        assert self.organization.name in confirmation.content.decode()
+
+        deleted = self.client.post(f"{ADMIN_URL}{block.pk}/delete/", data={"post": "yes"})
+
+        assert deleted.status_code == 302, deleted.content
+        assert not SandboxSenderOrganizationBlock.objects.filter(organization=self.organization).exists()
diff --git a/products/workflows/backend/tests/api/test_sandbox_sender.py b/products/workflows/backend/tests/api/test_sandbox_sender.py
index 45fd51429a48..b70307dd0c95 100644
--- a/products/workflows/backend/tests/api/test_sandbox_sender.py
+++ b/products/workflows/backend/tests/api/test_sandbox_sender.py
@@ -10,10 +10,12 @@
 from rest_framework import status
 
 from posthog.models.integration import Integration
-from posthog.models.organization import OrganizationMembership
+from posthog.models.organization import Organization, OrganizationMembership
 from posthog.models.personal_api_key import PersonalAPIKey
 from posthog.models.utils import hash_key_value
 
+from products.workflows.backend.models import SandboxSenderOrganizationBlock
+
 if TYPE_CHECKING:
     from rest_framework.response import _MonkeyPatchedResponse
 
@@ -114,6 +116,25 @@ def test_ensure_is_not_found_while_the_sandbox_sender_is_unavailable(
         assert not self._sandbox_rows().exists()
         assert self._provisioned_events() == []
 
+    def test_ensure_is_not_found_while_the_organization_is_blocked_and_keeps_existing_senders(self) -> None:
+        other_organization = Organization.objects.create(name="Other organization")
+        SandboxSenderOrganizationBlock.objects.create(organization=other_organization, reason="Abuse report")
+        block = SandboxSenderOrganizationBlock.objects.create(organization=self.organization, reason="Abuse report")
+
+        blocked = self._ensure()
+
+        assert blocked.status_code == status.HTTP_404_NOT_FOUND, blocked.json()
+        assert not self._sandbox_rows().exists()
+        assert self._provisioned_events() == []
+        block.delete()
+        unblocked = self._ensure()
+        assert unblocked.status_code == status.HTTP_200_OK, unblocked.json()
+        assert self._sandbox_rows().count() == 1
+        SandboxSenderOrganizationBlock.objects.create(organization=self.organization, reason="Abuse report")
+        reblocked = self._ensure()
+        assert reblocked.status_code == status.HTTP_404_NOT_FOUND, reblocked.json()
+        assert self._sandbox_rows().count() == 1
+
     @parameterized.expand(
         [
             ("read scope", "integration:read", status.HTTP_403_FORBIDDEN),