diff --git a/lib/towerops/billing/billing_notifier.ex b/lib/towerops/billing/billing_notifier.ex
new file mode 100644
index 00000000..748b4de7
--- /dev/null
+++ b/lib/towerops/billing/billing_notifier.ex
@@ -0,0 +1,101 @@
+defmodule Towerops.Billing.BillingNotifier do
+  @moduledoc """
+  Email notification service for billing events.
+
+  Sends emails for payment failures, subscription updates, and billing alerts.
+  """
+
+  use Gettext, backend: ToweropsWeb.Gettext
+
+  import Swoosh.Email
+  import ToweropsWeb.GettextHelpers
+
+  alias Towerops.Mailer
+  alias Towerops.Organizations
+
+  require Logger
+
+  defp deliver(recipient, subject, body) do
+    from_address = Application.get_env(:towerops, :mailer_from, {"Towerops", "hi@towerops.net"})
+
+    email =
+      new()
+      |> to(recipient)
+      |> from(from_address)
+      |> subject(subject)
+      |> text_body(body)
+
+    case Mailer.deliver(email) do
+      {:ok, _metadata} ->
+        Logger.info("Billing email sent to #{recipient}: #{subject}")
+        {:ok, email}
+
+      {:error, reason} = error ->
+        Logger.error("Failed to send billing email to #{recipient}: #{inspect(reason)}")
+        error
+    end
+  end
+
+  @doc """
+  Deliver payment failure notification to organization owners and admins.
+
+  Sends an email to all organization owners and admins informing them of a payment
+  failure and providing a link to update their payment method.
+  """
+  def deliver_payment_failed_notification(organization) do
+    # Get all owners and admins (people who can manage billing)
+    recipients =
+      organization.id
+      |> Organizations.list_organization_members()
+      |> Enum.filter(fn membership -> membership.role in [:owner, :admin] end)
+      |> Enum.map(fn membership -> membership.user end)
+
+    if Enum.empty?(recipients) do
+      Logger.warning("No owners or admins found for organization #{organization.slug} to notify about payment failure")
+
+      {:ok, []}
+    else
+      subject = t_email("Payment failed for %{org_name}", org_name: organization.name)
+
+      body =
+        t_email(
+          """
+          Hi,
+
+          We were unable to process the payment for your %{org_name} subscription on Towerops.
+
+          Your subscription is still active, but we'll retry the payment in a few days. To avoid service interruption, please update your payment method as soon as possible.
+
+          You can update your payment method here:
+          %{billing_url}
+
+          If you have any questions or need assistance, please don't hesitate to reply to this email.
+
+          Thank you,
+          Towerops Team
+          """,
+          org_name: organization.name,
+          billing_url: billing_portal_url(organization)
+        )
+
+      results =
+        Enum.map(recipients, fn user ->
+          deliver(user.email, subject, body)
+        end)
+
+      # Return success if at least one email was sent
+      if Enum.any?(results, &match?({:ok, _}, &1)) do
+        {:ok, results}
+      else
+        {:error, :all_emails_failed}
+      end
+    end
+  end
+
+  defp billing_portal_url(organization) do
+    # Generate URL to billing settings page
+    # In production, this should use the configured app URL
+    base_url = Application.get_env(:towerops, :app_url, "https://towerops.net")
+    "#{base_url}/o/#{organization.slug}/settings#billing"
+  end
+end
diff --git a/test/towerops/billing/billing_notifier_test.exs b/test/towerops/billing/billing_notifier_test.exs
new file mode 100644
index 00000000..cd43f99d
--- /dev/null
+++ b/test/towerops/billing/billing_notifier_test.exs
@@ -0,0 +1,108 @@
+defmodule Towerops.Billing.BillingNotifierTest do
+  use Towerops.DataCase, async: true
+
+  import Swoosh.TestAssertions
+  import Towerops.AccountsFixtures
+  import Towerops.OrganizationsFixtures
+
+  alias Towerops.Billing.BillingNotifier
+  alias Towerops.Organizations
+
+  describe "deliver_payment_failed_notification/1" do
+    test "sends email to organization owner" do
+      user = user_fixture()
+      organization = organization_fixture(user.id)
+
+      assert {:ok, _results} = BillingNotifier.deliver_payment_failed_notification(organization)
+
+      assert_email_sent(fn email ->
+        assert email.to == [{"", user.email}]
+        assert email.subject =~ "Payment failed"
+        assert email.subject =~ organization.name
+        assert email.text_body =~ organization.name
+        assert email.text_body =~ "unable to process the payment"
+        assert email.text_body =~ "/o/#{organization.slug}/settings#billing"
+      end)
+    end
+
+    test "sends email to all owners and admins" do
+      owner = user_fixture()
+      admin = user_fixture(%{email: "admin@example.com"})
+      member = user_fixture(%{email: "member@example.com"})
+      viewer = user_fixture(%{email: "viewer@example.com"})
+
+      organization = organization_fixture(owner.id)
+
+      # Add admin, member, and viewer
+      {:ok, _} =
+        Organizations.create_membership(%{
+          organization_id: organization.id,
+          user_id: admin.id,
+          role: :admin
+        })
+
+      {:ok, _} =
+        Organizations.create_membership(%{
+          organization_id: organization.id,
+          user_id: member.id,
+          role: :member
+        })
+
+      {:ok, _} =
+        Organizations.create_membership(%{
+          organization_id: organization.id,
+          user_id: viewer.id,
+          role: :viewer
+        })
+
+      assert {:ok, results} = BillingNotifier.deliver_payment_failed_notification(organization)
+
+      # Should send 2 emails (owner + admin only, not member or viewer)
+      assert length(results) == 2
+      assert Enum.all?(results, &match?({:ok, _}, &1))
+
+      # Check that owner and admin received emails
+      assert_email_sent(fn email -> email.to == [{"", owner.email}] end)
+      assert_email_sent(fn email -> email.to == [{"", admin.email}] end)
+    end
+
+    test "returns ok with empty list when no owners or admins exist" do
+      # Create organization with only member (no owner somehow)
+      user = user_fixture()
+      organization = organization_fixture(user.id)
+
+      # Delete the owner membership
+      membership = Organizations.get_membership(organization.id, user.id)
+      Towerops.Repo.delete!(membership)
+
+      assert {:ok, []} = BillingNotifier.deliver_payment_failed_notification(organization)
+
+      # No emails should be sent
+      assert_no_email_sent()
+    end
+
+    test "includes billing portal URL in email" do
+      user = user_fixture()
+      organization = organization_fixture(user.id)
+
+      assert {:ok, _results} = BillingNotifier.deliver_payment_failed_notification(organization)
+
+      assert_email_sent(fn email ->
+        email.text_body =~ "/o/#{organization.slug}/settings#billing"
+      end)
+    end
+
+    test "email contains helpful instructions" do
+      user = user_fixture()
+      organization = organization_fixture(user.id)
+
+      assert {:ok, _results} = BillingNotifier.deliver_payment_failed_notification(organization)
+
+      assert_email_sent(fn email ->
+        assert email.text_body =~ "update your payment method"
+        assert email.text_body =~ "retry the payment"
+        assert email.text_body =~ "avoid service interruption"
+      end)
+    end
+  end
+end