diff --git a/homeassistant/components/ecobee/const.py b/homeassistant/components/ecobee/const.py
index 44abafe8380..caf25690a9d 100644
--- a/homeassistant/components/ecobee/const.py
+++ b/homeassistant/components/ecobee/const.py
@@ -37,7 +37,7 @@ ECOBEE_MODEL_TO_NAME = {
     "vulcanSmart": "ecobee4 Smart",
 }
 
-PLATFORMS = ["binary_sensor", "climate", "sensor", "weather"]
+PLATFORMS = ["binary_sensor", "climate", "humidifier", "sensor", "weather"]
 
 MANUFACTURER = "ecobee"
 
diff --git a/homeassistant/components/ecobee/humidifier.py b/homeassistant/components/ecobee/humidifier.py
new file mode 100644
index 00000000000..5067d5080cb
--- /dev/null
+++ b/homeassistant/components/ecobee/humidifier.py
@@ -0,0 +1,123 @@
+"""Support for using humidifier with ecobee thermostats."""
+from datetime import timedelta
+
+from homeassistant.components.humidifier import HumidifierEntity
+from homeassistant.components.humidifier.const import (
+    DEFAULT_MAX_HUMIDITY,
+    DEFAULT_MIN_HUMIDITY,
+    DEVICE_CLASS_HUMIDIFIER,
+    MODE_AUTO,
+    SUPPORT_MODES,
+)
+
+from .const import DOMAIN
+
+SCAN_INTERVAL = timedelta(minutes=3)
+
+MODE_MANUAL = "manual"
+MODE_OFF = "off"
+
+
+async def async_setup_entry(hass, config_entry, async_add_entities):
+    """Set up the ecobee thermostat humidifier entity."""
+    data = hass.data[DOMAIN]
+    entities = []
+    for index in range(len(data.ecobee.thermostats)):
+        thermostat = data.ecobee.get_thermostat(index)
+        if thermostat["settings"]["hasHumidifier"]:
+            entities.append(EcobeeHumidifier(data, index))
+
+    async_add_entities(entities, True)
+
+
+class EcobeeHumidifier(HumidifierEntity):
+    """A humidifier class for an ecobee thermostat with humidifer attached."""
+
+    def __init__(self, data, thermostat_index):
+        """Initialize ecobee humidifier platform."""
+        self.data = data
+        self.thermostat_index = thermostat_index
+        self.thermostat = self.data.ecobee.get_thermostat(self.thermostat_index)
+        self._name = self.thermostat["name"]
+        self._last_humidifier_on_mode = MODE_MANUAL
+
+        self.update_without_throttle = False
+
+    async def async_update(self):
+        """Get the latest state from the thermostat."""
+        if self.update_without_throttle:
+            await self.data.update(no_throttle=True)
+            self.update_without_throttle = False
+        else:
+            await self.data.update()
+        self.thermostat = self.data.ecobee.get_thermostat(self.thermostat_index)
+        if self.mode != MODE_OFF:
+            self._last_humidifier_on_mode = self.mode
+
+    @property
+    def available_modes(self):
+        """Return the list of available modes."""
+        return [MODE_OFF, MODE_AUTO, MODE_MANUAL]
+
+    @property
+    def device_class(self):
+        """Return the device class type."""
+        return DEVICE_CLASS_HUMIDIFIER
+
+    @property
+    def is_on(self):
+        """Return True if the humidifier is on."""
+        return self.mode != MODE_OFF
+
+    @property
+    def max_humidity(self):
+        """Return the maximum humidity."""
+        return DEFAULT_MAX_HUMIDITY
+
+    @property
+    def min_humidity(self):
+        """Return the minimum humidity."""
+        return DEFAULT_MIN_HUMIDITY
+
+    @property
+    def mode(self):
+        """Return the current mode, e.g., off, auto, manual."""
+        return self.thermostat["settings"]["humidifierMode"]
+
+    @property
+    def name(self):
+        """Return the name of the ecobee thermostat."""
+        return self._name
+
+    @property
+    def supported_features(self):
+        """Return the list of supported features."""
+        return SUPPORT_MODES
+
+    @property
+    def target_humidity(self) -> int:
+        """Return the desired humidity set point."""
+        return int(self.thermostat["runtime"]["desiredHumidity"])
+
+    def set_mode(self, mode):
+        """Set humidifier mode (auto, off, manual)."""
+        if mode.lower() not in (self.available_modes):
+            raise ValueError(
+                f"Invalid mode value: {mode}  Valid values are {', '.join(self.available_modes)}."
+            )
+
+        self.data.ecobee.set_humidifier_mode(self.thermostat_index, mode)
+        self.update_without_throttle = True
+
+    def set_humidity(self, humidity):
+        """Set the humidity level."""
+        self.data.ecobee.set_humidity(self.thermostat_index, humidity)
+        self.update_without_throttle = True
+
+    def turn_off(self, **kwargs):
+        """Set humidifier to off mode."""
+        self.set_mode(MODE_OFF)
+
+    def turn_on(self, **kwargs):
+        """Set humidifier to on mode."""
+        self.set_mode(self._last_humidifier_on_mode)
diff --git a/tests/components/ecobee/common.py b/tests/components/ecobee/common.py
new file mode 100644
index 00000000000..0422b35f787
--- /dev/null
+++ b/tests/components/ecobee/common.py
@@ -0,0 +1,27 @@
+"""Common methods used across tests for Ecobee."""
+from unittest.mock import patch
+
+from homeassistant.components.ecobee.const import CONF_REFRESH_TOKEN, DOMAIN
+from homeassistant.const import CONF_API_KEY
+from homeassistant.setup import async_setup_component
+
+from tests.common import MockConfigEntry
+
+
+async def setup_platform(hass, platform):
+    """Set up the ecobee platform."""
+    mock_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={
+            CONF_API_KEY: "ABC123",
+            CONF_REFRESH_TOKEN: "EFG456",
+        },
+    )
+    mock_entry.add_to_hass(hass)
+
+    with patch("homeassistant.components.ecobee.const.PLATFORMS", [platform]):
+        assert await async_setup_component(hass, DOMAIN, {})
+
+    await hass.async_block_till_done()
+
+    return mock_entry
diff --git a/tests/components/ecobee/conftest.py b/tests/components/ecobee/conftest.py
new file mode 100644
index 00000000000..a7766af2ff9
--- /dev/null
+++ b/tests/components/ecobee/conftest.py
@@ -0,0 +1,17 @@
+"""Fixtures for tests."""
+import pytest
+
+from tests.common import load_fixture
+
+
+@pytest.fixture(autouse=True)
+def requests_mock_fixture(requests_mock):
+    """Fixture to provide a requests mocker."""
+    requests_mock.get(
+        "https://api.ecobee.com/1/thermostat",
+        text=load_fixture("ecobee/ecobee-data.json"),
+    )
+    requests_mock.post(
+        "https://api.ecobee.com/token",
+        text=load_fixture("ecobee/ecobee-token.json"),
+    )
diff --git a/tests/components/ecobee/test_climate.py b/tests/components/ecobee/test_climate.py
index 95b4b290b70..270c6cfec15 100644
--- a/tests/components/ecobee/test_climate.py
+++ b/tests/components/ecobee/test_climate.py
@@ -164,6 +164,7 @@ async def test_extra_state_attributes(ecobee_fixture, thermostat):
         "fan_min_on_time": 10,
         "equipment_running": "auxHeat2",
     } == thermostat.extra_state_attributes
+
     ecobee_fixture["equipmentStatus"] = "compCool1"
     assert {
         "fan": "off",
diff --git a/tests/components/ecobee/test_humidifier.py b/tests/components/ecobee/test_humidifier.py
new file mode 100644
index 00000000000..dd58decfb32
--- /dev/null
+++ b/tests/components/ecobee/test_humidifier.py
@@ -0,0 +1,130 @@
+"""The test for the ecobee thermostat humidifier module."""
+from unittest.mock import patch
+
+import pytest
+
+from homeassistant.components.ecobee.humidifier import MODE_MANUAL, MODE_OFF
+from homeassistant.components.humidifier import DOMAIN as HUMIDIFIER_DOMAIN
+from homeassistant.components.humidifier.const import (
+    ATTR_AVAILABLE_MODES,
+    ATTR_HUMIDITY,
+    ATTR_MAX_HUMIDITY,
+    ATTR_MIN_HUMIDITY,
+    DEFAULT_MAX_HUMIDITY,
+    DEFAULT_MIN_HUMIDITY,
+    DEVICE_CLASS_HUMIDIFIER,
+    MODE_AUTO,
+    SERVICE_SET_HUMIDITY,
+    SERVICE_SET_MODE,
+    SUPPORT_MODES,
+)
+from homeassistant.const import (
+    ATTR_DEVICE_CLASS,
+    ATTR_ENTITY_ID,
+    ATTR_FRIENDLY_NAME,
+    ATTR_MODE,
+    ATTR_SUPPORTED_FEATURES,
+    SERVICE_TURN_OFF,
+    SERVICE_TURN_ON,
+    STATE_OFF,
+)
+
+from .common import setup_platform
+
+DEVICE_ID = "humidifier.ecobee"
+
+
+async def test_attributes(hass):
+    """Test the humidifier attributes are correct."""
+    await setup_platform(hass, HUMIDIFIER_DOMAIN)
+
+    state = hass.states.get(DEVICE_ID)
+    assert state.state == STATE_OFF
+    assert state.attributes.get(ATTR_MIN_HUMIDITY) == DEFAULT_MIN_HUMIDITY
+    assert state.attributes.get(ATTR_MAX_HUMIDITY) == DEFAULT_MAX_HUMIDITY
+    assert state.attributes.get(ATTR_HUMIDITY) == 40
+    assert state.attributes.get(ATTR_AVAILABLE_MODES) == [
+        MODE_OFF,
+        MODE_AUTO,
+        MODE_MANUAL,
+    ]
+    assert state.attributes.get(ATTR_FRIENDLY_NAME) == "ecobee"
+    assert state.attributes.get(ATTR_DEVICE_CLASS) == DEVICE_CLASS_HUMIDIFIER
+    assert state.attributes.get(ATTR_SUPPORTED_FEATURES) == SUPPORT_MODES
+
+
+async def test_turn_on(hass):
+    """Test the humidifer can be turned on."""
+    with patch("pyecobee.Ecobee.set_humidifier_mode") as mock_turn_on:
+        await setup_platform(hass, HUMIDIFIER_DOMAIN)
+
+        await hass.services.async_call(
+            HUMIDIFIER_DOMAIN,
+            SERVICE_TURN_ON,
+            {ATTR_ENTITY_ID: DEVICE_ID},
+            blocking=True,
+        )
+        await hass.async_block_till_done()
+        mock_turn_on.assert_called_once_with(0, "manual")
+
+
+async def test_turn_off(hass):
+    """Test the humidifer can be turned off."""
+    with patch("pyecobee.Ecobee.set_humidifier_mode") as mock_turn_off:
+        await setup_platform(hass, HUMIDIFIER_DOMAIN)
+
+        await hass.services.async_call(
+            HUMIDIFIER_DOMAIN,
+            SERVICE_TURN_OFF,
+            {ATTR_ENTITY_ID: DEVICE_ID},
+            blocking=True,
+        )
+        await hass.async_block_till_done()
+        mock_turn_off.assert_called_once_with(0, STATE_OFF)
+
+
+async def test_set_mode(hass):
+    """Test the humidifer can change modes."""
+    with patch("pyecobee.Ecobee.set_humidifier_mode") as mock_set_mode:
+        await setup_platform(hass, HUMIDIFIER_DOMAIN)
+
+        await hass.services.async_call(
+            HUMIDIFIER_DOMAIN,
+            SERVICE_SET_MODE,
+            {ATTR_ENTITY_ID: DEVICE_ID, ATTR_MODE: MODE_AUTO},
+            blocking=True,
+        )
+        await hass.async_block_till_done()
+        mock_set_mode.assert_called_once_with(0, MODE_AUTO)
+
+        await hass.services.async_call(
+            HUMIDIFIER_DOMAIN,
+            SERVICE_SET_MODE,
+            {ATTR_ENTITY_ID: DEVICE_ID, ATTR_MODE: MODE_MANUAL},
+            blocking=True,
+        )
+        await hass.async_block_till_done()
+        mock_set_mode.assert_called_with(0, MODE_MANUAL)
+
+        with pytest.raises(ValueError):
+            await hass.services.async_call(
+                HUMIDIFIER_DOMAIN,
+                SERVICE_SET_MODE,
+                {ATTR_ENTITY_ID: DEVICE_ID, ATTR_MODE: "ModeThatDoesntExist"},
+                blocking=True,
+            )
+
+
+async def test_set_humidity(hass):
+    """Test the humidifer can set humidity level."""
+    with patch("pyecobee.Ecobee.set_humidity") as mock_set_humidity:
+        await setup_platform(hass, HUMIDIFIER_DOMAIN)
+
+        await hass.services.async_call(
+            HUMIDIFIER_DOMAIN,
+            SERVICE_SET_HUMIDITY,
+            {ATTR_ENTITY_ID: DEVICE_ID, ATTR_HUMIDITY: 60},
+            blocking=True,
+        )
+        await hass.async_block_till_done()
+        mock_set_humidity.assert_called_once_with(0, 60)
diff --git a/tests/fixtures/ecobee/ecobee-data.json b/tests/fixtures/ecobee/ecobee-data.json
new file mode 100644
index 00000000000..2727103c9b1
--- /dev/null
+++ b/tests/fixtures/ecobee/ecobee-data.json
@@ -0,0 +1,43 @@
+{
+    "thermostatList": [
+        {"name": "ecobee",
+            "program": {
+                "climates": [
+                    {"name": "Climate1", "climateRef": "c1"},
+                    {"name": "Climate2", "climateRef": "c2"}
+                ],
+                "currentClimateRef": "c1"
+            },
+            "runtime": {
+                "actualTemperature": 300,
+                "actualHumidity": 15,
+                "desiredHeat": 400,
+                "desiredCool": 200,
+                "desiredFanMode": "on",
+                "desiredHumidity": 40
+            },
+            "settings": {
+                "hvacMode": "auto",
+                "heatStages": 1,
+                "coolStages": 1,
+                "fanMinOnTime": 10,
+                "heatCoolMinDelta": 50,
+                "holdAction": "nextTransition",
+                "hasHumidifier": true,
+                "humidifierMode": "off",
+                "humidity": "30"
+            },
+            "equipmentStatus": "fan",
+            "events": [
+                {
+                    "name": "Event1",
+                    "running": true,
+                    "type": "hold",
+                    "holdClimateRef": "away",
+                    "endDate": "2022-01-01 10:00:00",
+                    "startDate": "2022-02-02 11:00:00"
+                }
+            ]}
+    ]
+
+}
\ No newline at end of file
diff --git a/tests/fixtures/ecobee/ecobee-token.json b/tests/fixtures/ecobee/ecobee-token.json
new file mode 100644
index 00000000000..6ee8305a592
--- /dev/null
+++ b/tests/fixtures/ecobee/ecobee-token.json
@@ -0,0 +1,7 @@
+{
+    "access_token": "Rc7JE8P7XUgSCPogLOx2VLMfITqQQrjg",
+    "token_type": "Bearer",
+    "expires_in": 3599,
+    "refresh_token": "og2Obost3ucRo1ofo0EDoslGltmFMe2g",
+    "scope": "smartWrite" 
+}   
\ No newline at end of file