diff --git a/homeassistant/components/tplink/diagnostics.py b/homeassistant/components/tplink/diagnostics.py
index 5121def2e47..c81356ee658 100644
--- a/homeassistant/components/tplink/diagnostics.py
+++ b/homeassistant/components/tplink/diagnostics.py
@@ -6,6 +6,7 @@ from typing import Any
 from homeassistant.components.diagnostics import async_redact_data
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant
+from homeassistant.helpers.device_registry import format_mac
 
 from .const import DOMAIN
 from .coordinator import TPLinkDataUpdateCoordinator
@@ -36,6 +37,8 @@ async def async_get_config_entry_diagnostics(
 ) -> dict[str, Any]:
     """Return diagnostics for a config entry."""
     coordinator: TPLinkDataUpdateCoordinator = hass.data[DOMAIN][entry.entry_id]
+    oui = format_mac(coordinator.device.mac)[:8].upper()
     return async_redact_data(
-        {"device_last_response": coordinator.device.internal_state}, TO_REDACT
+        {"device_last_response": coordinator.device.internal_state, "oui": oui},
+        TO_REDACT,
     )
diff --git a/tests/components/tplink/test_diagnostics.py b/tests/components/tplink/test_diagnostics.py
index 5b3fe4803a4..3ef42c48b2f 100644
--- a/tests/components/tplink/test_diagnostics.py
+++ b/tests/components/tplink/test_diagnostics.py
@@ -14,17 +14,19 @@ from tests.typing import ClientSessionGenerator
 
 
 @pytest.mark.parametrize(
-    ("mocked_dev", "fixture_file", "sysinfo_vars"),
+    ("mocked_dev", "fixture_file", "sysinfo_vars", "expected_oui"),
     [
         (
             _mocked_bulb(),
             "tplink-diagnostics-data-bulb-kl130.json",
             ["mic_mac", "deviceId", "oemId", "hwId", "alias"],
+            "AA:BB:CC",
         ),
         (
             _mocked_plug(),
             "tplink-diagnostics-data-plug-hs110.json",
             ["mac", "deviceId", "oemId", "hwId", "alias", "longitude_i", "latitude_i"],
+            "AA:BB:CC",
         ),
     ],
 )
@@ -34,6 +36,7 @@ async def test_diagnostics(
     mocked_dev: SmartDevice,
     fixture_file: str,
     sysinfo_vars: list[str],
+    expected_oui: str | None,
 ):
     """Test diagnostics for config entry."""
     diagnostics_data = json.loads(load_fixture(fixture_file, "tplink"))
@@ -58,3 +61,5 @@ async def test_diagnostics(
     sysinfo = last_response["system"]["get_sysinfo"]
     for var in sysinfo_vars:
         assert sysinfo[var] == "**REDACTED**"
+
+    assert result["oui"] == expected_oui