diff --git a/custom_components/pyscript/__init__.py b/custom_components/pyscript/__init__.py
index 47758bc..8d3ad83 100644
--- a/custom_components/pyscript/__init__.py
+++ b/custom_components/pyscript/__init__.py
@@ -4,7 +4,9 @@
 import json
 import logging
 import os
+import sys
 
+import pkg_resources
 import voluptuous as vol
 
 from homeassistant.config import async_hass_config_yaml
@@ -19,6 +21,7 @@
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.restore_state import RestoreStateData
 from homeassistant.loader import bind_hass
+from homeassistant.requirements import async_process_requirements
 
 from .const import (
     CONF_ALLOW_ALL_IMPORTS,
@@ -27,6 +30,8 @@
     DOMAIN,
     FOLDER,
     LOGGER_PATH,
+    REQUIREMENTS_FILE,
+    REQUIREMENTS_PATHS,
     SERVICE_JUPYTER_KERNEL_START,
     UNSUB_LISTENERS,
 )
@@ -38,6 +43,17 @@
 from .state import State
 from .trigger import TrigTime
 
+if sys.version_info[:2] >= (3, 8):
+    from importlib.metadata import (  # pylint: disable=no-name-in-module,import-error
+        PackageNotFoundError,
+        version as installed_version,
+    )
+else:
+    from importlib_metadata import (  # pylint: disable=import-error
+        PackageNotFoundError,
+        version as installed_version,
+    )
+
 _LOGGER = logging.getLogger(LOGGER_PATH)
 
 PYSCRIPT_SCHEMA = vol.Schema(
@@ -133,6 +149,7 @@ async def async_setup_entry(hass, config_entry):
 
     State.set_pyscript_config(config_entry.data)
 
+    await install_requirements(hass)
     await load_scripts(hass, config_entry.data)
 
     async def reload_scripts_handler(call):
@@ -150,6 +167,7 @@ async def reload_scripts_handler(call):
 
         await unload_scripts(global_ctx_only=global_ctx_only)
 
+        await install_requirements(hass)
         await load_scripts(hass, config_entry.data, global_ctx_only=global_ctx_only)
 
         start_global_contexts(global_ctx_only=global_ctx_only)
@@ -250,6 +268,73 @@ async def unload_scripts(global_ctx_only=None, unload_all=False):
         await GlobalContextMgr.delete(global_ctx_name)
 
 
+@bind_hass
+def load_all_requirement_lines(hass, requirements_paths, requirements_file):
+    """Load all lines from requirements_file located in requirements_paths."""
+    all_requirements = {}
+    for root in requirements_paths:
+        for requirements_path in glob.glob(os.path.join(hass.config.path(FOLDER), root, requirements_file)):
+            with open(requirements_path, "r") as requirements_fp:
+                all_requirements[requirements_path] = requirements_fp.readlines()
+
+    return all_requirements
+
+
+@bind_hass
+async def install_requirements(hass):
+    """Install missing requirements from requirements.txt."""
+    all_requirements = await hass.async_add_executor_job(
+        load_all_requirement_lines, hass, REQUIREMENTS_PATHS, REQUIREMENTS_FILE
+    )
+    requirements_to_install = []
+    for requirements_path, pkg_lines in all_requirements.items():
+        for pkg in pkg_lines:
+            # Remove inline comments which are accepted by pip but not by Home
+            # Assistant's installation method.
+            # https://rosettacode.org/wiki/Strip_comments_from_a_string#Python
+            i = pkg.find("#")
+            if i >= 0:
+                pkg = pkg[:i]
+            pkg = pkg.strip()
+
+            if not pkg:
+                continue
+
+            try:
+                # Attempt to get version of package. Do nothing if it's found since
+                # we want to use the version that's already installed to be safe
+                requirement = pkg_resources.Requirement.parse(pkg)
+                requirement_installed_version = installed_version(requirement.project_name)
+
+                if requirement_installed_version in requirement:
+                    _LOGGER.debug("`%s` already found", requirement.project_name)
+                else:
+                    _LOGGER.warning(
+                        (
+                            "`%s` already found but found version `%s` does not"
+                            " match requirement. Keeping found version."
+                        ),
+                        requirement.project_name,
+                        requirement_installed_version,
+                    )
+            except PackageNotFoundError:
+                # Since package wasn't found, add it to installation list
+                _LOGGER.debug("%s not found, adding it to package installation list", pkg)
+                requirements_to_install.append(pkg)
+            except ValueError:
+                # Not valid requirements line so it can be skipped
+                _LOGGER.debug("Ignoring `%s` because it is not a valid package", pkg)
+        if requirements_to_install:
+            _LOGGER.info(
+                "Installing the following packages from %s: %s",
+                requirements_path,
+                ", ".join(requirements_to_install),
+            )
+            await async_process_requirements(hass, DOMAIN, requirements_to_install)
+        else:
+            _LOGGER.debug("All packages in %s are already available", requirements_path)
+
+
 @bind_hass
 async def load_scripts(hass, data, global_ctx_only=None):
     """Load all python scripts in FOLDER."""
diff --git a/custom_components/pyscript/const.py b/custom_components/pyscript/const.py
index d453189..82c0652 100644
--- a/custom_components/pyscript/const.py
+++ b/custom_components/pyscript/const.py
@@ -14,6 +14,9 @@
 
 LOGGER_PATH = "custom_components.pyscript"
 
+REQUIREMENTS_FILE = "requirements.txt"
+REQUIREMENTS_PATHS = ("", "apps/*", "modules/*")
+
 ALLOWED_IMPORTS = {
     "black",
     "cmath",
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..2e0369e
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,10 @@
+"""Test configuration for pyscript."""
+from pytest import fixture
+from pytest_homeassistant_custom_component.async_mock import patch
+
+
+@fixture(autouse=True)
+def bypass_package_install_fixture():
+    """Bypass package installation."""
+    with patch("custom_components.pyscript.async_process_requirements"):
+        yield
diff --git a/tests/test_decorator_errors.py b/tests/test_decorator_errors.py
index 9d0845e..fd48499 100644
--- a/tests/test_decorator_errors.py
+++ b/tests/test_decorator_errors.py
@@ -23,6 +23,16 @@ async def setup_script(hass, notify_q, now, source):
         "custom_components.pyscript.trigger.dt_now", return_value=now
     ), patch(
         "homeassistant.config.load_yaml_config_file", return_value={}
+    ), patch(
+        "custom_components.pyscript.load_all_requirement_lines",
+        return_value={
+            "/some/config/dir/pyscript/requirements.txt": [
+                "pytube==9.7.0\n",
+                "# another test comment\n",
+                "pykakasi==2.0.1 # test comment\n",
+                "\n",
+            ]
+        },
     ):
         assert await async_setup_component(hass, "pyscript", {DOMAIN: {}})
 
diff --git a/tests/test_function.py b/tests/test_function.py
index 29e5efe..4a333c0 100644
--- a/tests/test_function.py
+++ b/tests/test_function.py
@@ -109,6 +109,16 @@ async def setup_script(hass, notify_q, now, source):
         "custom_components.pyscript.trigger.dt_now", return_value=now
     ), patch(
         "homeassistant.config.load_yaml_config_file", return_value={DOMAIN: {CONF_ALLOW_ALL_IMPORTS: True}}
+    ), patch(
+        "custom_components.pyscript.load_all_requirement_lines",
+        return_value={
+            "/some/config/dir/pyscript/requirements.txt": [
+                "pytube==9.7.0\n",
+                "# another test comment\n",
+                "pykakasi==2.0.1 # test comment\n",
+                "\n",
+            ]
+        },
     ):
         assert await async_setup_component(hass, "pyscript", {DOMAIN: {CONF_ALLOW_ALL_IMPORTS: True}})
 
diff --git a/tests/test_init.py b/tests/test_init.py
index a670998..cef329c 100644
--- a/tests/test_init.py
+++ b/tests/test_init.py
@@ -32,6 +32,16 @@ async def setup_script(hass, notify_q, now, source):
         "custom_components.pyscript.trigger.dt_now", return_value=now
     ), patch(
         "homeassistant.config.load_yaml_config_file", return_value={}
+    ), patch(
+        "custom_components.pyscript.load_all_requirement_lines",
+        return_value={
+            "/some/config/dir/pyscript/requirements.txt": [
+                "pytube==9.7.0\n",
+                "# another test comment\n",
+                "pykakasi==2.0.1 # test comment\n",
+                "\n",
+            ]
+        },
     ):
         assert await async_setup_component(hass, "pyscript", {DOMAIN: {}})
 
@@ -446,6 +456,16 @@ def func5(var_name=None, value=None):
             "custom_components.pyscript.trigger.dt_now", return_value=now
         ), patch(
             "homeassistant.config.load_yaml_config_file", return_value={}
+        ), patch(
+            "custom_components.pyscript.load_all_requirement_lines",
+            return_value={
+                "/some/config/dir/pyscript/requirements.txt": [
+                    "pytube==9.7.0\n",
+                    "# another test comment\n",
+                    "pykakasi==2.0.1 # test comment\n",
+                    "\n",
+                ]
+            },
         ):
             reload_param = {}
             if i % 2 == 1:
@@ -482,3 +502,19 @@ async def test_misc_errors(hass, caplog):
     assert "State class is not meant to be instantiated" in caplog.text
     assert "Event class is not meant to be instantiated" in caplog.text
     assert "TrigTime class is not meant to be instantiated" in caplog.text
+
+
+async def test_install_requirements(hass):
+    """Test install_requirements function."""
+    with patch("custom_components.pyscript.async_hass_config_yaml", return_value={}), patch(
+        "custom_components.pyscript.async_process_requirements"
+    ) as install_requirements:
+        await setup_script(hass, None, dt(2020, 7, 1, 11, 59, 59, 999999), "")
+        assert install_requirements.called
+        assert install_requirements.call_args[0][2] == ["pytube==9.7.0", "pykakasi==2.0.1"]
+        install_requirements.reset_mock()
+        # Because in tests, packages are not installed, we fake that they are
+        # installed so we can test that we don't attempt to install them
+        with patch("custom_components.pyscript.installed_version", return_value="2.0.1"):
+            await hass.services.async_call("pyscript", "reload", {}, blocking=True)
+            assert not install_requirements.called
diff --git a/tests/test_jupyter.py b/tests/test_jupyter.py
index db1d6fe..0c71459 100644
--- a/tests/test_jupyter.py
+++ b/tests/test_jupyter.py
@@ -117,6 +117,16 @@ async def setup_script(hass, now, source, no_connect=False):
         "custom_components.pyscript.trigger.dt_now", return_value=now
     ), patch(
         "homeassistant.config.load_yaml_config_file", return_value={}
+    ), patch(
+        "custom_components.pyscript.load_all_requirement_lines",
+        return_value={
+            "/some/config/dir/pyscript/requirements.txt": [
+                "pytube==9.7.0\n",
+                "# another test comment\n",
+                "pykakasi==2.0.1 # test comment\n",
+                "\n",
+            ]
+        },
     ):
         assert await async_setup_component(hass, "pyscript", {DOMAIN: {}})
 
diff --git a/tests/test_unique.py b/tests/test_unique.py
index a82b29e..f1536ce 100644
--- a/tests/test_unique.py
+++ b/tests/test_unique.py
@@ -23,6 +23,16 @@ async def setup_script(hass, notify_q, now, source):
         "custom_components.pyscript.trigger.dt_now", return_value=now
     ), patch(
         "homeassistant.config.load_yaml_config_file", return_value={}
+    ), patch(
+        "custom_components.pyscript.load_all_requirement_lines",
+        return_value={
+            "/some/config/dir/pyscript/requirements.txt": [
+                "pytube==9.7.0\n",
+                "# another test comment\n",
+                "pykakasi==2.0.1 # test comment\n",
+                "\n",
+            ]
+        },
     ):
         assert await async_setup_component(hass, "pyscript", {DOMAIN: {}})