diff --git a/homeassistant/components/sms/__init__.py b/homeassistant/components/sms/__init__.py
index b8d46a4aec5..e78fda305da 100644
--- a/homeassistant/components/sms/__init__.py
+++ b/homeassistant/components/sms/__init__.py
@@ -1,13 +1,15 @@
 """The sms component."""
 import logging
 
-import gammu  # pylint: disable=import-error, no-member
 import voluptuous as vol
 
+from homeassistant.config_entries import SOURCE_IMPORT, ConfigEntry
 from homeassistant.const import CONF_DEVICE
+from homeassistant.core import HomeAssistant
 from homeassistant.helpers import config_validation as cv
 
-from .const import DOMAIN
+from .const import DOMAIN, SMS_GATEWAY
+from .gateway import create_sms_gateway
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -17,17 +19,38 @@ CONFIG_SCHEMA = vol.Schema(
 )
 
 
-def setup(hass, config):
+async def async_setup(hass, config):
     """Configure Gammu state machine."""
-    conf = config[DOMAIN]
-    device = conf.get(CONF_DEVICE)
-    gateway = gammu.StateMachine()  # pylint: disable=no-member
-    try:
-        gateway.SetConfig(0, dict(Device=device, Connection="at"))
-        gateway.Init()
-    except gammu.GSMError as exc:  # pylint: disable=no-member
-        _LOGGER.error("Failed to initialize, error %s", exc)
-        return False
-    else:
-        hass.data[DOMAIN] = gateway
+    hass.data.setdefault(DOMAIN, {})
+    sms_config = config.get(DOMAIN, {})
+    if not sms_config:
         return True
+
+    hass.async_create_task(
+        hass.config_entries.flow.async_init(
+            DOMAIN, context={"source": SOURCE_IMPORT}, data=sms_config,
+        )
+    )
+
+    return True
+
+
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry):
+    """Configure Gammu state machine."""
+
+    device = entry.data[CONF_DEVICE]
+    config = {"Device": device, "Connection": "at"}
+    gateway = await create_sms_gateway(config, hass)
+    if not gateway:
+        return False
+    hass.data[DOMAIN][SMS_GATEWAY] = gateway
+
+    return True
+
+
+async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry):
+    """Unload a config entry."""
+
+    gateway = hass.data[DOMAIN].pop(SMS_GATEWAY)
+    await gateway.terminate_async()
+    return True
diff --git a/homeassistant/components/sms/config_flow.py b/homeassistant/components/sms/config_flow.py
new file mode 100644
index 00000000000..148360416a2
--- /dev/null
+++ b/homeassistant/components/sms/config_flow.py
@@ -0,0 +1,74 @@
+"""Config flow for SMS integration."""
+import logging
+
+import gammu  # pylint: disable=import-error, no-member
+import voluptuous as vol
+
+from homeassistant import config_entries, core, exceptions
+from homeassistant.const import CONF_DEVICE
+
+from .const import DOMAIN  # pylint:disable=unused-import
+from .gateway import create_sms_gateway
+
+_LOGGER = logging.getLogger(__name__)
+
+DATA_SCHEMA = vol.Schema({vol.Required(CONF_DEVICE): str})
+
+
+async def get_imei_from_config(hass: core.HomeAssistant, data):
+    """Validate the user input allows us to connect.
+
+    Data has the keys from DATA_SCHEMA with values provided by the user.
+    """
+    device = data[CONF_DEVICE]
+    config = {"Device": device, "Connection": "at"}
+    gateway = await create_sms_gateway(config, hass)
+    if not gateway:
+        raise CannotConnect
+    try:
+        imei = await gateway.get_imei_async()
+    except gammu.GSMError:  # pylint: disable=no-member
+        raise CannotConnect
+    finally:
+        await gateway.terminate_async()
+
+    # Return info that you want to store in the config entry.
+    return imei
+
+
+class SMSFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
+    """Handle a config flow for SMS integration."""
+
+    VERSION = 1
+    CONNECTION_CLASS = config_entries.CONN_CLASS_LOCAL_POLL
+
+    async def async_step_user(self, user_input=None):
+        """Handle the initial step."""
+        if self._async_current_entries():
+            return self.async_abort(reason="single_instance_allowed")
+        errors = {}
+        if user_input is not None:
+            try:
+                imei = await get_imei_from_config(self.hass, user_input)
+            except CannotConnect:
+                errors["base"] = "cannot_connect"
+            except Exception:  # pylint: disable=broad-except
+                _LOGGER.exception("Unexpected exception")
+                errors["base"] = "unknown"
+
+            if not errors:
+                await self.async_set_unique_id(imei)
+                self._abort_if_unique_id_configured()
+                return self.async_create_entry(title=imei, data=user_input)
+
+        return self.async_show_form(
+            step_id="user", data_schema=DATA_SCHEMA, errors=errors
+        )
+
+    async def async_step_import(self, user_input):
+        """Handle import."""
+        return await self.async_step_user(user_input)
+
+
+class CannotConnect(exceptions.HomeAssistantError):
+    """Error to indicate we cannot connect."""
diff --git a/homeassistant/components/sms/const.py b/homeassistant/components/sms/const.py
index aff2b704e05..b73e7954fc1 100644
--- a/homeassistant/components/sms/const.py
+++ b/homeassistant/components/sms/const.py
@@ -1,3 +1,4 @@
 """Constants for sms Component."""
 
 DOMAIN = "sms"
+SMS_GATEWAY = "SMS_GATEWAY"
diff --git a/homeassistant/components/sms/gateway.py b/homeassistant/components/sms/gateway.py
new file mode 100644
index 00000000000..8a75808f751
--- /dev/null
+++ b/homeassistant/components/sms/gateway.py
@@ -0,0 +1,42 @@
+"""The sms gateway to interact with a GSM modem."""
+import logging
+
+import gammu  # pylint: disable=import-error, no-member
+from gammu.asyncworker import (  # pylint: disable=import-error, no-member
+    GammuAsyncWorker,
+)
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class Gateway:
+    """SMS gateway to interact with a GSM modem."""
+
+    def __init__(self, worker, hass):
+        """Initialize the sms gateway."""
+        self._worker = worker
+
+    async def send_sms_async(self, message):
+        """Send sms message via the worker."""
+        return await self._worker.send_sms_async(message)
+
+    async def get_imei_async(self):
+        """Get the IMEI of the device."""
+        return await self._worker.get_imei_async()
+
+    async def terminate_async(self):
+        """Terminate modem connection."""
+        return await self._worker.terminate_async()
+
+
+async def create_sms_gateway(config, hass):
+    """Create the sms gateway."""
+    try:
+        worker = GammuAsyncWorker()
+        worker.configure(config)
+        await worker.init_async()
+        gateway = Gateway(worker, hass)
+        return gateway
+    except gammu.GSMError as exc:  # pylint: disable=no-member
+        _LOGGER.error("Failed to initialize, error %s", exc)
+        return None
diff --git a/homeassistant/components/sms/manifest.json b/homeassistant/components/sms/manifest.json
index 8b65ac77e59..c3c7db2aa61 100644
--- a/homeassistant/components/sms/manifest.json
+++ b/homeassistant/components/sms/manifest.json
@@ -1,7 +1,8 @@
 {
   "domain": "sms",
   "name": "SMS notifications via GSM-modem",
+  "config_flow": true,
   "documentation": "https://www.home-assistant.io/integrations/sms",
-  "requirements": ["python-gammu==2.12"],
+  "requirements": ["python-gammu==3.0"],
   "codeowners": ["@ocalvo"]
 }
diff --git a/homeassistant/components/sms/notify.py b/homeassistant/components/sms/notify.py
index f39ae8153bd..0b867b2e0a5 100644
--- a/homeassistant/components/sms/notify.py
+++ b/homeassistant/components/sms/notify.py
@@ -8,7 +8,7 @@ from homeassistant.components.notify import PLATFORM_SCHEMA, BaseNotificationSer
 from homeassistant.const import CONF_NAME, CONF_RECIPIENT
 import homeassistant.helpers.config_validation as cv
 
-from .const import DOMAIN
+from .const import DOMAIN, SMS_GATEWAY
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -19,8 +19,18 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
 
 def get_service(hass, config, discovery_info=None):
     """Get the SMS notification service."""
-    gateway = hass.data[DOMAIN]
-    number = config[CONF_RECIPIENT]
+
+    if SMS_GATEWAY not in hass.data[DOMAIN]:
+        _LOGGER.error("SMS gateway not found, cannot initialize service")
+        return
+
+    gateway = hass.data[DOMAIN][SMS_GATEWAY]
+
+    if discovery_info is None:
+        number = config[CONF_RECIPIENT]
+    else:
+        number = discovery_info[CONF_RECIPIENT]
+
     return SMSNotificationService(gateway, number)
 
 
@@ -32,7 +42,7 @@ class SMSNotificationService(BaseNotificationService):
         self.gateway = gateway
         self.number = number
 
-    def send_message(self, message="", **kwargs):
+    async def send_message(self, message="", **kwargs):
         """Send SMS message."""
         smsinfo = {
             "Class": -1,
@@ -53,6 +63,6 @@ class SMSNotificationService(BaseNotificationService):
             encoded_message["Number"] = self.number
             try:
                 # Actually send the message
-                self.gateway.SendSMS(encoded_message)
+                await self.gateway.send_sms_async(encoded_message)
             except gammu.GSMError as exc:  # pylint: disable=no-member
                 _LOGGER.error("Sending to %s failed: %s", self.number, exc)
diff --git a/homeassistant/components/sms/strings.json b/homeassistant/components/sms/strings.json
new file mode 100644
index 00000000000..6f92631e2e1
--- /dev/null
+++ b/homeassistant/components/sms/strings.json
@@ -0,0 +1,19 @@
+{
+  "config": {
+    "step": {
+      "user": {
+        "title": "Connect to the modem",
+        "data": { "device": "Device" }
+      }
+    },
+    "error": {
+      "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]",
+      "unknown": "[%key:common::config_flow::error::unknown%]"
+    },
+    "abort": {
+      "already_configured": "[%key:common::config_flow::abort::already_configured_device%]",
+      "single_instance_allowed": "[%key:common::config_flow::abort::single_instance_allowed%]"
+    }
+    
+  }
+}
diff --git a/homeassistant/generated/config_flows.py b/homeassistant/generated/config_flows.py
index cf950edb901..54678007eb7 100644
--- a/homeassistant/generated/config_flows.py
+++ b/homeassistant/generated/config_flows.py
@@ -139,6 +139,7 @@ FLOWS = [
     "smappee",
     "smartthings",
     "smhi",
+    "sms",
     "solaredge",
     "solarlog",
     "soma",
diff --git a/requirements_all.txt b/requirements_all.txt
index ec06e60110d..a6ea39b314c 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -1694,7 +1694,7 @@ python-family-hub-local==0.0.2
 python-forecastio==1.4.0
 
 # homeassistant.components.sms
-# python-gammu==2.12
+# python-gammu==3.0
 
 # homeassistant.components.gc100
 python-gc100==1.0.3a