diff --git a/app/code/core/Mage/Core/Helper/EnvironmentConfigLoader.php b/app/code/core/Mage/Core/Helper/EnvironmentConfigLoader.php
new file mode 100644
index 00000000000..61abc39e84e
--- /dev/null
+++ b/app/code/core/Mage/Core/Helper/EnvironmentConfigLoader.php
@@ -0,0 +1,158 @@
+<?php
+/**
+ * OpenMage
+ *
+ * This source file is subject to the Open Software License (OSL 3.0)
+ * that is bundled with this package in the file LICENSE.txt.
+ * It is also available at https://opensource.org/license/osl-3-0-php
+ *
+ * @category   Mage
+ * @package    Mage_Core
+ * @copyright  Copyright (c) 2024 The OpenMage Contributors (https://www.openmage.org)
+ * @license    https://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
+ */
+
+/**
+ * Core Environment helper
+ *
+ * @category   Mage
+ * @package    Mage_Core
+ */
+class Mage_Core_Helper_EnvironmentConfigLoader extends Mage_Core_Helper_Abstract
+{
+    protected const ENV_STARTS_WITH = 'OPENMAGE_CONFIG';
+    protected const ENV_KEY_SEPARATOR = '__';
+    protected const CONFIG_KEY_DEFAULT = 'DEFAULT';
+    protected const CONFIG_KEY_WEBSITES = 'WEBSITES';
+    protected const CONFIG_KEY_STORES = 'STORES';
+    /**
+     * To be used as regex condition
+     */
+    protected const ALLOWED_CHARS = ['A-Z', '-', '_'];
+    protected $_moduleName = 'Mage_Core';
+    protected array $envStore = [];
+
+    /**
+     * Load configuration values from ENV variables into xml config object
+     *
+     * Environment variables work on this schema:
+     *
+     * self::ENV_STARTS_WITH . self::ENV_KEY_SEPARATOR (OPENMAGE_CONFIG__)
+     *        ^ Prefix (required)
+     *                  <SCOPE>__
+     *                     ^ Where scope is DEFAULT, WEBSITES__<WEBSITE_CODE> or STORES__<STORE_CODE>
+     *                           <SYSTEM_VARIABLE_NAME>
+     *                                   ^ Where GROUP, SECTION and FIELD are separated by self::ENV_KEY_SEPARATOR
+     *
+     * Each example will override the 'general/store_information/name' value.
+     * Override from the default configuration:
+     * @example OPENMAGE_CONFIG__DEFAULT__GENERAL__STORE_INFORMATION__NAME=default
+     * Override the website 'base' configuration:
+     * @example OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__STORE_INFORMATION__NAME=website
+     * Override the store 'german' configuration:
+     * @example OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__STORE_INFORMATION__NAME=store_german
+     *
+     * @param Varien_Simplexml_Config $xmlConfig
+     * @return void
+     */
+    public function overrideEnvironment(Varien_Simplexml_Config $xmlConfig)
+    {
+        $env = $this->getEnv();
+
+        foreach ($env as $configKey => $value) {
+            if (!$this->isConfigKeyValid($configKey)) {
+                continue;
+            }
+
+            list($configKeyParts, $scope) = $this->getConfigKey($configKey);
+
+            switch ($scope) {
+                case static::CONFIG_KEY_DEFAULT:
+                    list($_, $_, $section, $group, $field) = $configKeyParts;
+                    $path = $this->buildPath($section, $group, $field);
+                    $xmlConfig->setNode($this->buildNodePath($scope, $path), $value);
+                    break;
+
+                case static::CONFIG_KEY_WEBSITES:
+                case static::CONFIG_KEY_STORES:
+                    list($_, $_, $code, $section, $group, $field) = $configKeyParts;
+                    $path = $this->buildPath($section, $group, $field);
+                    $nodePath = sprintf('%s/%s/%s', strtolower($scope), strtolower($code), $path);
+                    $xmlConfig->setNode($nodePath, $value);
+                    break;
+            }
+        }
+    }
+
+    /**
+     * @internal method mostly for mocking
+     */
+    public function setEnvStore(array $envStorage): void
+    {
+        $this->envStore = $envStorage;
+    }
+
+    public function getEnv(): array
+    {
+        if (empty($this->envStore)) {
+            $this->envStore = getenv();
+        }
+        return $this->envStore;
+    }
+
+    protected function getConfigKey(string $configKey): array
+    {
+        $configKeyParts = array_filter(
+            explode(
+                static::ENV_KEY_SEPARATOR,
+                $configKey
+            ),
+            'trim'
+        );
+        list($_, $scope) = $configKeyParts;
+        return array($configKeyParts, $scope);
+    }
+
+    protected function isConfigKeyValid(string $configKey): bool
+    {
+        if (!str_starts_with($configKey, static::ENV_STARTS_WITH)) {
+            return false;
+        }
+
+        $sectionGroupFieldRegexp = sprintf('([%s]*)', implode('', static::ALLOWED_CHARS));
+        $allowedChars = sprintf('[%s]', implode('', static::ALLOWED_CHARS));
+        $regexp = '/' . static::ENV_STARTS_WITH . static::ENV_KEY_SEPARATOR . '(WEBSITES' . static::ENV_KEY_SEPARATOR
+            . $allowedChars . '+|DEFAULT|STORES' . static::ENV_KEY_SEPARATOR . $allowedChars . '+)'
+            . static::ENV_KEY_SEPARATOR . $sectionGroupFieldRegexp
+            . static::ENV_KEY_SEPARATOR . $sectionGroupFieldRegexp
+            . static::ENV_KEY_SEPARATOR . $sectionGroupFieldRegexp . '/';
+        // /OPENMAGE_CONFIG__(WEBSITES__[A-Z-_]+|DEFAULT|STORES__[A-Z-_]+)__([A-Z-_]*)__([A-Z-_]*)__([A-Z-_]*)/
+
+        return preg_match($regexp, $configKey);
+    }
+
+    /**
+     * Build configuration path.
+     *
+     * @param string $section
+     * @param string $group
+     * @param string $field
+     * @return string
+     */
+    protected function buildPath(string $section, string $group, string $field): string
+    {
+        return strtolower(implode('/', [$section, $group, $field]));
+    }
+
+    /**
+     * Build configuration node path.
+     *
+     * @param string $scope
+     * @param string $path
+     * @return string
+     */
+    protected function buildNodePath(string $scope, string $path): string
+    {
+        return strtolower($scope) . '/' . $path;
+    }
+}
diff --git a/app/code/core/Mage/Core/Model/App.php b/app/code/core/Mage/Core/Model/App.php
index a44360011fd..9989bd21744 100644
--- a/app/code/core/Mage/Core/Model/App.php
+++ b/app/code/core/Mage/Core/Model/App.php
@@ -442,6 +442,7 @@ protected function _initModules()
                         Varien_Profiler::stop('mage::app::init::apply_db_schema_updates');
                     }
                     $this->_config->loadDb();
+                    $this->_config->loadEnv();
                     $this->_config->saveCache();
                 }
             } finally {
diff --git a/app/code/core/Mage/Core/Model/Config.php b/app/code/core/Mage/Core/Model/Config.php
index b4498800c31..e5a6fb86b6d 100644
--- a/app/code/core/Mage/Core/Model/Config.php
+++ b/app/code/core/Mage/Core/Model/Config.php
@@ -320,6 +320,7 @@ public function init($options = [])
                     $this->_useCache = false;
                     $this->loadModules();
                     $this->loadDb();
+                    $this->loadEnv();
                     $this->saveCache();
                 }
             } finally {
@@ -422,6 +423,23 @@ public function loadDb()
         return $this;
     }
 
+    /**
+     * Load environment variables and override config
+     *
+     * @return self
+     */
+    public function loadEnv(): Mage_Core_Model_Config
+    {
+        if ($this->_isLocalConfigLoaded && Mage::isInstalled()) {
+            Varien_Profiler::start('config/load-env');
+            /** @var Mage_Core_Helper_EnvironmentConfigLoader $environmentConfigLoaderHelper */
+            $environmentConfigLoaderHelper = Mage::helper('core/environmentConfigLoader');
+            $environmentConfigLoaderHelper->overrideEnvironment($this);
+            Varien_Profiler::stop('config/load-env');
+        }
+        return $this;
+    }
+
     /**
      * Reinitialize configuration
      *
diff --git a/dev/tests/unit/Mage/Core/Helper/EnvironmentConfigLoaderTest.php b/dev/tests/unit/Mage/Core/Helper/EnvironmentConfigLoaderTest.php
new file mode 100644
index 00000000000..ed7911d29ba
--- /dev/null
+++ b/dev/tests/unit/Mage/Core/Helper/EnvironmentConfigLoaderTest.php
@@ -0,0 +1,315 @@
+<?php
+declare(strict_types=1);
+
+namespace OpenMage\Tests\Unit\Core\Helper;
+
+use PHPUnit\Framework\TestCase;
+use Mage_Core_Helper_EnvironmentConfigLoader;
+use Mage_Core_Model_Config;
+
+class TestEnvLoaderHelper extends Mage_Core_Helper_EnvironmentConfigLoader {
+    public function exposedBuildPath(string $section, string $group, string $field): string
+    {
+        return $this->buildPath($section, $group, $field);
+    }
+
+    public function exposedBuildNodePath(string $scope, string $path): string
+    {
+        return $this->buildNodePath($scope, $path);
+    }
+}
+
+class EnvironmentConfigLoaderTest extends TestCase
+{
+    public function setup(): void
+    {
+        \Mage::setRoot('');
+    }
+
+    public function testBuildPath()
+    {
+        $environmentConfigLoaderHelper = new TestEnvLoaderHelper();
+        $path = $environmentConfigLoaderHelper->exposedBuildPath('GENERAL', 'STORE_INFORMATION', 'NAME');
+        $this->assertEquals('general/store_information/name', $path);
+    }
+
+    public function testBuildNodePath()
+    {
+        $environmentConfigLoaderHelper = new TestEnvLoaderHelper();
+        $nodePath = $environmentConfigLoaderHelper->exposedBuildNodePath('DEFAULT', 'general/store_information/name');
+        $this->assertEquals('default/general/store_information/name', $nodePath);
+    }
+
+    public function test_xml_has_test_strings()
+    {
+        $xmlStruct = $this->getTestXml();
+        $xml = new \Varien_Simplexml_Config();
+        $xml->loadString($xmlStruct);
+        $this->assertEquals('test_default', (string)$xml->getNode('default/general/store_information/name'));
+        $this->assertEquals('test_website', (string)$xml->getNode('websites/base/general/store_information/name'));
+        $this->assertEquals('test_store', (string)$xml->getNode('stores/german/general/store_information/name'));
+    }
+
+    /**
+     * @dataProvider env_overrides_correct_config_keys
+     * @test
+     */
+    public function env_overrides_for_valid_config_keys(array $config)
+    {
+        $xmlStruct = $this->getTestXml();
+
+        $xmlDefault = new \Varien_Simplexml_Config();
+        $xmlDefault->loadString($xmlStruct);
+        $xml = new \Varien_Simplexml_Config();
+        $xml->loadString($xmlStruct);
+
+        // act
+        $loader = new Mage_Core_Helper_EnvironmentConfigLoader();
+        $loader->setEnvStore([
+            $config['env_path'] => $config['value']
+        ]);
+        $loader->overrideEnvironment($xml);
+
+        $configPath = $config['xml_path'];
+        $defaultValue = $xmlDefault->getNode($configPath);
+        $valueAfterOverride = $xml->getNode($configPath);
+
+        // assert
+        $this->assertNotEquals((string)$defaultValue, (string)$valueAfterOverride, 'Default value was not overridden.');
+    }
+
+    public function env_overrides_correct_config_keys(): array
+    {
+        $defaultPath = 'OPENMAGE_CONFIG__DEFAULT__GENERAL__STORE_INFORMATION__NAME';
+        $defaultPathWithDash = 'OPENMAGE_CONFIG__DEFAULT__GENERAL__FOO-BAR__NAME';
+        $defaultPathWithUnderscore = 'OPENMAGE_CONFIG__DEFAULT__GENERAL__FOO_BAR__NAME';
+
+        $websitePath = 'OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__STORE_INFORMATION__NAME';
+        $websiteWithDashPath = 'OPENMAGE_CONFIG__WEBSITES__BASE-AT__GENERAL__STORE_INFORMATION__NAME';
+        $websiteWithUnderscorePath = 'OPENMAGE_CONFIG__WEBSITES__BASE_CH__GENERAL__STORE_INFORMATION__NAME';
+
+        $storeWithDashPath = 'OPENMAGE_CONFIG__STORES__GERMAN-AT__GENERAL__STORE_INFORMATION__NAME';
+        $storeWithUnderscorePath = 'OPENMAGE_CONFIG__STORES__GERMAN_CH__GENERAL__STORE_INFORMATION__NAME';
+        $storePath = 'OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__STORE_INFORMATION__NAME';
+
+        return [
+            [
+                'Case DEFAULT overrides.' => [
+                    'case'     => 'DEFAULT',
+                    'xml_path' => 'default/general/store_information/name',
+                    'env_path' => $defaultPath,
+                    'value'    => 'default_new_value'
+                ]
+            ],
+            [
+                'Case DEFAULT overrides.' => [
+                    'case'     => 'DEFAULT',
+                    'xml_path' => 'default/general/foo-bar/name',
+                    'env_path' => $defaultPathWithDash,
+                    'value'    => 'baz'
+                ]
+            ],
+            [
+                'Case DEFAULT overrides.' => [
+                    'case'     => 'DEFAULT',
+                    'xml_path' => 'default/general/foo_bar/name',
+                    'env_path' => $defaultPathWithUnderscore,
+                    'value'    => 'baz'
+                ]
+            ],
+            [
+                'Case STORE overrides.' => [
+                    'case'     => 'STORE',
+                    'xml_path' => 'stores/german/general/store_information/name',
+                    'env_path' => $storePath,
+                    'value'    => 'store_new_value'
+                ]
+            ],
+            [
+                'Case STORE overrides.' => [
+                    'case'     => 'STORE',
+                    'xml_path' => 'stores/german-at/general/store_information/name',
+                    'env_path' => $storeWithDashPath,
+                    'value'    => 'store_new_value'
+                ]
+            ],
+            [
+                'Case STORE overrides.' => [
+                    'case'     => 'STORE',
+                    'xml_path' => 'stores/german_ch/general/store_information/name',
+                    'env_path' => $storeWithUnderscorePath,
+                    'value'    => 'store_new_value'
+                ]
+            ],
+            [
+                'Case WEBSITE overrides.' => [
+                    'case'     => 'WEBSITE',
+                    'xml_path' => 'websites/base/general/store_information/name',
+                    'env_path' => $websitePath,
+                    'value'    => 'website_new_value'
+                ]
+            ],
+            [
+                'Case WEBSITE overrides.' => [
+                    'case'     => 'WEBSITE',
+                    'xml_path' => 'websites/base_ch/general/store_information/name',
+                    'env_path' => $websiteWithUnderscorePath,
+                    'value'    => 'website_new_value'
+                ]
+            ],
+            [
+                'Case WEBSITE overrides.' => [
+                    'case'     => 'WEBSITE',
+                    'xml_path' => 'websites/base-at/general/store_information/name',
+                    'env_path' => $websiteWithDashPath,
+                    'value'    => 'website_new_value'
+                ]
+            ]
+        ];
+    }
+
+    /**
+     * @dataProvider env_does_not_override_on_wrong_config_keys
+     * @test
+     */
+    public function env_does_not_override_for_invalid_config_keys(array $config)
+    {
+        $xmlStruct = $this->getTestXml();
+
+        $xmlDefault = new \Varien_Simplexml_Config();
+        $xmlDefault->loadString($xmlStruct);
+        $xml = new \Varien_Simplexml_Config();
+        $xml->loadString($xmlStruct);
+
+        $defaultValue = 'test_default';
+        $this->assertEquals($defaultValue, (string)$xml->getNode('default/general/store_information/name'));
+        $defaultWebsiteValue = 'test_website';
+        $this->assertEquals($defaultWebsiteValue, (string)$xml->getNode('websites/base/general/store_information/name'));
+        $defaultStoreValue = 'test_store';
+        $this->assertEquals($defaultStoreValue, (string)$xml->getNode('stores/german/general/store_information/name'));
+
+        // act
+        $loader = new Mage_Core_Helper_EnvironmentConfigLoader();
+        $loader->setEnvStore([
+            $config['path'] => $config['value']
+        ]);
+        $loader->overrideEnvironment($xml);
+
+        switch ($config['case']) {
+            case 'DEFAULT':
+                $valueAfterCheck = $xml->getNode('default/general/store_information/name');
+                break;
+            case 'STORE':
+                $valueAfterCheck = $xml->getNode('stores/german/general/store_information/name');
+                break;
+            case 'WEBSITE':
+                $valueAfterCheck = $xml->getNode('websites/base/general/store_information/name');
+                break;
+        }
+
+        // assert
+        $this->assertTrue(!str_contains('value_will_not_be_changed', (string)$valueAfterCheck), 'Default value was wrongfully overridden.');
+    }
+
+    public function env_does_not_override_on_wrong_config_keys(): array
+    {
+        $defaultPath = 'OPENMAGE_CONFIG__DEFAULT__GENERAL__ST';
+        $websitePath = 'OPENMAGE_CONFIG__WEBSITES__BASE__GENERAL__ST';
+        $storePath = 'OPENMAGE_CONFIG__STORES__GERMAN__GENERAL__ST';
+        return [
+            [
+                'Case DEFAULT with ' . $defaultPath . ' will not override.' => [
+                    'case'  => 'DEFAULT',
+                    'path'  => $defaultPath,
+                    'value' => 'default_value_will_not_be_changed'
+                ]
+            ],
+            [
+                'Case STORE with ' . $storePath . ' will not override.' => [
+                    'case'  => 'STORE',
+                    'path'  => $storePath,
+                    'value' => 'store_value_will_not_be_changed'
+                ]
+            ],
+            [
+                'Case WEBSITE with ' . $websitePath . ' will not override.' => [
+                    'case'  => 'WEBSITE',
+                    'path'  => $websitePath,
+                    'value' => 'website_value_will_not_be_changed'
+                ]
+            ]
+        ];
+    }
+
+    /**
+     * @return string
+     */
+    public function getTestXml(): string
+    {
+        return <<<XML
+<?xml version="1.0" encoding="UTF-8" ?>
+<config>
+    <default>
+        <general>
+            <store_information>
+                    <name>test_default</name>
+            </store_information>
+            <foo-bar>
+                    <name>test_default</name>
+            </foo-bar>
+            <foo_bar>
+                    <name>test_default</name>
+            </foo_bar>
+        </general>
+    </default>
+    
+    <websites>
+        <base>
+            <general>
+                <store_information>
+                        <name>test_website</name>
+                </store_information>
+            </general>
+        </base>
+        <base-at>
+            <general>
+                <store_information>
+                        <name>test_website</name>
+                </store_information>
+            </general>
+        </base-at>
+        <base_ch>
+            <general>
+                <store_information>
+                        <name>test_website</name>
+                </store_information>
+            </general>
+        </base_ch>
+    </websites>
+    <stores>
+        <german>
+            <general>
+                <store_information>
+                        <name>test_store</name>
+                </store_information>
+            </general>
+        </german>
+        <german-at>
+            <general>
+                <store_information>
+                        <name>test_store</name>
+                </store_information>
+            </general>
+        </german-at>
+        <german_ch>
+            <general>
+                <store_information>
+                        <name>test_store</name>
+                </store_information>
+            </general>
+        </german_ch>
+    </stores>
+</config>
+XML;
+    }
+}