diff --git a/pkgs/development/python-modules/pyotgw/default.nix b/pkgs/development/python-modules/pyotgw/default.nix
new file mode 100644
index 00000000000..b48c190ca1e
--- /dev/null
+++ b/pkgs/development/python-modules/pyotgw/default.nix
@@ -0,0 +1,41 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, pyserial-asyncio
+, pytest-asyncio
+, pytestCheckHook
+, pythonOlder
+}:
+
+buildPythonPackage rec {
+  pname = "pyotgw";
+  version = "unstable-2021-03-25";
+  disabled = pythonOlder "3.7";
+
+  src = fetchFromGitHub {
+    owner = "mvn23";
+    repo = pname;
+    rev = "1854ef4ffb907524ff457ba558e4979ba7fabd02";
+    sha256 = "0zckd85dmzpz0drcgx16ly6kzh1f1slcxb9lrcf81wh1p4q9bcaa";
+  };
+
+  propagatedBuildInputs = [
+    pyserial-asyncio
+  ];
+
+  checkInputs = [
+    pytest-asyncio
+    pytestCheckHook
+  ];
+
+  pytestFlagsArray = [ "tests" ];
+
+  pythonImportsCheck = [ "pyotgw" ];
+
+  meta = with lib; {
+    description = "Python module to interact the OpenTherm Gateway";
+    homepage = "https://github.com/mvn23/pyotgw";
+    license = with licenses; [ gpl3Plus ];
+    maintainers = with maintainers; [ fab ];
+  };
+}
diff --git a/pkgs/servers/home-assistant/component-packages.nix b/pkgs/servers/home-assistant/component-packages.nix
index cf8c0641bc7..b6e8dedf2ec 100644
--- a/pkgs/servers/home-assistant/component-packages.nix
+++ b/pkgs/servers/home-assistant/component-packages.nix
@@ -598,7 +598,7 @@
     "openhome" = ps: with ps; [ openhomedevice ];
     "opensensemap" = ps: with ps; [ opensensemap-api ];
     "opensky" = ps: with ps; [ ];
-    "opentherm_gw" = ps: with ps; [ ]; # missing inputs: pyotgw
+    "opentherm_gw" = ps: with ps; [ pyotgw ];
     "openuv" = ps: with ps; [ pyopenuv ];
     "openweathermap" = ps: with ps; [ pyowm ];
     "opnsense" = ps: with ps; [ pyopnsense ];
diff --git a/pkgs/servers/home-assistant/default.nix b/pkgs/servers/home-assistant/default.nix
index cb455738080..960535b5ec6 100644
--- a/pkgs/servers/home-assistant/default.nix
+++ b/pkgs/servers/home-assistant/default.nix
@@ -336,6 +336,7 @@ in with py.pkgs; buildPythonApplication rec {
     "omnilogic"
     "ondilo_ico"
     "openerz"
+    "opentherm_gw"
     "ozw"
     "panel_custom"
     "panel_iframe"
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 163fdf72b82..cc390b22213 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -5861,6 +5861,8 @@ in {
     inherit (pkgs) lz4;
   };
 
+  pyotgw = callPackage ../development/python-modules/pyotgw { };
+
   pyotp = callPackage ../development/python-modules/pyotp { };
 
   pyowm = callPackage ../development/python-modules/pyowm { };