diff --git a/homeassistant/components/ntfy/diagnostics.py b/homeassistant/components/ntfy/diagnostics.py
new file mode 100644
index 00000000000..5be239dfef6
--- /dev/null
+++ b/homeassistant/components/ntfy/diagnostics.py
@@ -0,0 +1,29 @@
+"""Diagnostics platform for ntfy integration."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from yarl import URL
+
+from homeassistant.components.diagnostics import REDACTED
+from homeassistant.const import CONF_URL
+from homeassistant.core import HomeAssistant
+
+from . import NtfyConfigEntry
+
+
+async def async_get_config_entry_diagnostics(
+    hass: HomeAssistant, config_entry: NtfyConfigEntry
+) -> dict[str, Any]:
+    """Return diagnostics for a config entry."""
+
+    url = URL(config_entry.data[CONF_URL])
+    return {
+        CONF_URL: (
+            url.human_repr()
+            if url.host == "ntfy.sh"
+            else url.with_host(REDACTED).human_repr()
+        ),
+        "topics": dict(config_entry.subentries),
+    }
diff --git a/homeassistant/components/ntfy/quality_scale.yaml b/homeassistant/components/ntfy/quality_scale.yaml
index 84ec1d82b7c..0d075f0014b 100644
--- a/homeassistant/components/ntfy/quality_scale.yaml
+++ b/homeassistant/components/ntfy/quality_scale.yaml
@@ -49,7 +49,7 @@ rules:
 
   # Gold
   devices: done
-  diagnostics: todo
+  diagnostics: done
   discovery-update-info: todo
   discovery: todo
   docs-data-update: todo
diff --git a/tests/components/ntfy/snapshots/test_diagnostics.ambr b/tests/components/ntfy/snapshots/test_diagnostics.ambr
new file mode 100644
index 00000000000..3dd464f8670
--- /dev/null
+++ b/tests/components/ntfy/snapshots/test_diagnostics.ambr
@@ -0,0 +1,24 @@
+# serializer version: 1
+# name: test_diagnostics
+  dict({
+    'topics': dict({
+      'ABCDEF': dict({
+        'data': dict({
+          'topic': 'mytopic',
+        }),
+        'subentry_id': 'ABCDEF',
+        'subentry_type': 'topic',
+        'title': 'mytopic',
+        'unique_id': 'mytopic',
+      }),
+    }),
+    'url': 'https://ntfy.sh/',
+  })
+# ---
+# name: test_diagnostics_redacted_url
+  dict({
+    'topics': dict({
+    }),
+    'url': 'http://**redacted**/',
+  })
+# ---
diff --git a/tests/components/ntfy/test_diagnostics.py b/tests/components/ntfy/test_diagnostics.py
new file mode 100644
index 00000000000..a4aa3ee6aa7
--- /dev/null
+++ b/tests/components/ntfy/test_diagnostics.py
@@ -0,0 +1,55 @@
+"""Tests for ntfy diagnostics."""
+
+import pytest
+from syrupy.assertion import SnapshotAssertion
+
+from homeassistant.components.ntfy.const import DOMAIN
+from homeassistant.const import CONF_URL
+from homeassistant.core import HomeAssistant
+
+from tests.common import MockConfigEntry
+from tests.components.diagnostics import get_diagnostics_for_config_entry
+from tests.typing import ClientSessionGenerator
+
+
+@pytest.mark.usefixtures("mock_aiontfy")
+async def test_diagnostics(
+    hass: HomeAssistant,
+    hass_client: ClientSessionGenerator,
+    config_entry: MockConfigEntry,
+    snapshot: SnapshotAssertion,
+) -> None:
+    """Test diagnostics."""
+
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+    assert (
+        await get_diagnostics_for_config_entry(hass, hass_client, config_entry)
+        == snapshot
+    )
+
+
+@pytest.mark.usefixtures("mock_aiontfy")
+async def test_diagnostics_redacted_url(
+    hass: HomeAssistant,
+    hass_client: ClientSessionGenerator,
+    snapshot: SnapshotAssertion,
+) -> None:
+    """Test diagnostics redacted URL."""
+    config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        title="mydomain",
+        data={
+            CONF_URL: "http://mydomain/",
+        },
+        entry_id="123456789",
+        subentries_data=[],
+    )
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+    assert (
+        await get_diagnostics_for_config_entry(hass, hass_client, config_entry)
+        == snapshot
+    )