diff --git a/homeassistant/components/systemmonitor/sensor.py b/homeassistant/components/systemmonitor/sensor.py
index e70bccf0833..be277f8b565 100644
--- a/homeassistant/components/systemmonitor/sensor.py
+++ b/homeassistant/components/systemmonitor/sensor.py
@@ -118,6 +118,17 @@ def get_ip_address(
     return None
 
 
+def get_python3_num_fds(
+    entity: SystemMonitorSensor,
+) -> int | None:
+    """Return num_fds from python3 process."""
+    processes = entity.coordinator.data.processes
+    for proc in processes:
+        if proc.name() == "python3":
+            return proc.num_fds()
+    return None
+
+
 @dataclass(frozen=True, kw_only=True)
 class SysMonitorSensorEntityDescription(SensorEntityDescription):
     """Describes System Monitor sensor entities."""
@@ -369,6 +380,13 @@ SENSOR_TYPES: dict[str, SysMonitorSensorEntityDescription] = {
         value_fn=lambda entity: entity.coordinator.data.swap.percent,
         add_to_update=lambda entity: ("swap", ""),
     ),
+    "python3_num_fds": SysMonitorSensorEntityDescription(
+        key="python3_num_fds",
+        translation_key="python3_num_fds",
+        state_class=SensorStateClass.MEASUREMENT,
+        value_fn=get_python3_num_fds,
+        add_to_update=lambda entity: ("processes", ""),
+    ),
 }
 
 
@@ -566,6 +584,18 @@ async def async_setup_entry(
                     is_enabled,
                 )
             )
+        if _type == "python3_num_fds":
+            argument = ""
+            loaded_resources.add(slugify(f"{_type}_{argument}"))
+            entities.append(
+                SystemMonitorSensor(
+                    coordinator,
+                    sensor_description,
+                    entry.entry_id,
+                    argument,
+                    True,  # Enabled by default
+                )
+            )
 
     # Ensure legacy imported disk_* resources are loaded if they are not part
     # of mount points automatically discovered
diff --git a/homeassistant/components/systemmonitor/strings.json b/homeassistant/components/systemmonitor/strings.json
index 134fe390357..d0108993b6e 100644
--- a/homeassistant/components/systemmonitor/strings.json
+++ b/homeassistant/components/systemmonitor/strings.json
@@ -100,6 +100,9 @@
       },
       "swap_use_percent": {
         "name": "Swap usage"
+      },
+      "python3_num_fds": {
+        "name": "Python3 open file descriptors"
       }
     }
   }
diff --git a/tests/components/systemmonitor/conftest.py b/tests/components/systemmonitor/conftest.py
index 5f0a7a5c76d..0efbe6327a2 100644
--- a/tests/components/systemmonitor/conftest.py
+++ b/tests/components/systemmonitor/conftest.py
@@ -27,12 +27,13 @@ def mock_sys_platform() -> Generator[None]:
 class MockProcess(Process):
     """Mock a Process class."""
 
-    def __init__(self, name: str, ex: bool = False) -> None:
+    def __init__(self, name: str, ex: bool = False, num_fds: int = 3) -> None:
         """Initialize the process."""
         super().__init__(1)
         self._name = name
         self._ex = ex
         self._create_time = 1708700400
+        self._num_fds = num_fds
 
     def name(self):
         """Return a name."""
@@ -40,6 +41,10 @@ class MockProcess(Process):
             raise NoSuchProcess(1, self._name)
         return self._name
 
+    def num_fds(self):
+        """Return open file descriptors."""
+        return self._num_fds
+
 
 @pytest.fixture
 def mock_setup_entry() -> Generator[AsyncMock]:
diff --git a/tests/components/systemmonitor/snapshots/test_sensor.ambr b/tests/components/systemmonitor/snapshots/test_sensor.ambr
index 8108e4777c8..de2eb56f88c 100644
--- a/tests/components/systemmonitor/snapshots/test_sensor.ambr
+++ b/tests/components/systemmonitor/snapshots/test_sensor.ambr
@@ -114,16 +114,6 @@
 # name: test_sensor[System Monitor Last boot - state]
   '2024-02-24T15:00:00+00:00'
 # ---
-# name: test_sensor[System Monitor Load (15 min) - attributes]
-  ReadOnlyDict({
-    'friendly_name': 'System Monitor Load (15 min)',
-    'icon': 'mdi:cpu-64-bit',
-    'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
-  })
-# ---
-# name: test_sensor[System Monitor Load (15 min) - state]
-  '3'
-# ---
 # name: test_sensor[System Monitor Load (1 min) - attributes]
   ReadOnlyDict({
     'friendly_name': 'System Monitor Load (1 min)',
@@ -134,6 +124,16 @@
 # name: test_sensor[System Monitor Load (1 min) - state]
   '1'
 # ---
+# name: test_sensor[System Monitor Load (15 min) - attributes]
+  ReadOnlyDict({
+    'friendly_name': 'System Monitor Load (15 min)',
+    'icon': 'mdi:cpu-64-bit',
+    'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
+  })
+# ---
+# name: test_sensor[System Monitor Load (15 min) - state]
+  '3'
+# ---
 # name: test_sensor[System Monitor Load (5 min) - attributes]
   ReadOnlyDict({
     'friendly_name': 'System Monitor Load (5 min)',
@@ -322,6 +322,15 @@
 # name: test_sensor[System Monitor Processor use - state]
   '10'
 # ---
+# name: test_sensor[System Monitor Python3 open file descriptors - attributes]
+  ReadOnlyDict({
+    'friendly_name': 'System Monitor Python3 open file descriptors',
+    'state_class': <SensorStateClass.MEASUREMENT: 'measurement'>,
+  })
+# ---
+# name: test_sensor[System Monitor Python3 open file descriptors - state]
+  '3'
+# ---
 # name: test_sensor[System Monitor Swap free - attributes]
   ReadOnlyDict({
     'device_class': 'data_size',
diff --git a/tests/components/systemmonitor/test_sensor.py b/tests/components/systemmonitor/test_sensor.py
index a5f5e7623e9..3c4d41b8a58 100644
--- a/tests/components/systemmonitor/test_sensor.py
+++ b/tests/components/systemmonitor/test_sensor.py
@@ -18,6 +18,8 @@ from homeassistant.const import STATE_UNAVAILABLE, STATE_UNKNOWN
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers import entity_registry as er
 
+from .conftest import MockProcess
+
 from tests.common import MockConfigEntry, async_fire_time_changed
 
 
@@ -453,7 +455,7 @@ async def test_remove_obsolete_entities(
                 mock_added_config_entry.entry_id
             )
         )
-        == 37
+        == 38
     )
 
     entity_registry.async_update_entity(
@@ -494,7 +496,7 @@ async def test_remove_obsolete_entities(
                 mock_added_config_entry.entry_id
             )
         )
-        == 38
+        == 39
     )
 
     assert (
@@ -544,3 +546,56 @@ async def test_no_duplicate_disk_entities(
     assert disk_sensor.state == "60.0"
 
     assert "Platform systemmonitor does not generate unique IDs." not in caplog.text
+
+
+@pytest.mark.usefixtures("entity_registry_enabled_by_default")
+async def test_python3_num_fds(
+    hass: HomeAssistant,
+    mock_psutil: Mock,
+    mock_os: Mock,
+    entity_registry: er.EntityRegistry,
+    snapshot: SnapshotAssertion,
+    freezer: FrozenDateTimeFactory,
+) -> None:
+    """Test python3 open file descriptors sensor."""
+    mock_config_entry = MockConfigEntry(
+        title="System Monitor",
+        domain=DOMAIN,
+        data={},
+        options={
+            "resources": [
+                "disk_use_percent_/",
+                "disk_use_percent_/home/notexist/",
+                "memory_free_",
+                "network_out_eth0",
+                "process_python3",
+            ],
+        },
+    )
+    mock_config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(mock_config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    num_fds_sensor = hass.states.get(
+        "sensor.system_monitor_python3_open_file_descriptors"
+    )
+    assert num_fds_sensor is not None
+    assert num_fds_sensor.state == "3"
+    assert num_fds_sensor.attributes == {
+        "state_class": "measurement",
+        "friendly_name": "System Monitor Python3 open file descriptors",
+    }
+
+    _process = MockProcess("python3", num_fds=5)
+    assert _process.num_fds() == 5
+    mock_psutil.process_iter.return_value = [_process]
+
+    freezer.tick(timedelta(minutes=1))
+    async_fire_time_changed(hass)
+    await hass.async_block_till_done(wait_background_tasks=True)
+
+    num_fds_sensor = hass.states.get(
+        "sensor.system_monitor_python3_open_file_descriptors"
+    )
+    assert num_fds_sensor is not None
+    assert num_fds_sensor.state == "5"