diff --git a/src/Task/BuiltIn/Composer/DumpAutoloadTask.php b/src/Task/BuiltIn/Composer/DumpAutoloadTask.php
index b778413..39e44da 100644
--- a/src/Task/BuiltIn/Composer/DumpAutoloadTask.php
+++ b/src/Task/BuiltIn/Composer/DumpAutoloadTask.php
@@ -43,10 +43,9 @@ class DumpAutoloadTask extends AbstractTask
 
     protected function getOptions()
     {
-        $userOptions = $this->runtime->getConfigOption('composer', []);
         $options = array_merge(
             ['path' => 'composer', 'flags' => '--optimize'],
-            (is_array($userOptions) ? $userOptions : []),
+            $this->runtime->getMergedEnvAndConfigOption('composer', [], []),
             $this->options
         );
 
diff --git a/src/Task/BuiltIn/Composer/InstallTask.php b/src/Task/BuiltIn/Composer/InstallTask.php
index ce97361..5596864 100644
--- a/src/Task/BuiltIn/Composer/InstallTask.php
+++ b/src/Task/BuiltIn/Composer/InstallTask.php
@@ -43,10 +43,9 @@ class InstallTask extends AbstractTask
 
     protected function getOptions()
     {
-        $userOptions = $this->runtime->getConfigOption('composer', []);
         $options = array_merge(
             ['path' => 'composer', 'flags' => '--optimize-autoloader'],
-            (is_array($userOptions) ? $userOptions : []),
+            $this->runtime->getMergedEnvAndConfigOption('composer', [], []),
             $this->options
         );
 
diff --git a/tests/Command/BuiltIn/DeployCommandMiscTasksTest.php b/tests/Command/BuiltIn/DeployCommandMiscTasksTest.php
index 4d5efd6..a4beb90 100644
--- a/tests/Command/BuiltIn/DeployCommandMiscTasksTest.php
+++ b/tests/Command/BuiltIn/DeployCommandMiscTasksTest.php
@@ -80,6 +80,36 @@ class DeployCommandMiscTasksTest extends TestCase
         $this->assertEquals(0, $tester->getStatusCode());
     }
 
+    public function testComposerEnvFlags()
+    {
+        $application = new MageApplicationMockup(__DIR__ . '/../../Resources/composer-env.yml');
+
+        /** @var AbstractCommand $command */
+        $command = $application->find('deploy');
+        $this->assertTrue($command instanceof DeployCommand);
+
+        $tester = new CommandTester($command);
+        $tester->execute(['command' => $command->getName(), 'environment' => 'test']);
+
+        $ranCommands = $application->getRuntime()->getRanCommands();
+
+        $testCase = array(
+            0 => '/usr/foobar/composer install --prefer-source',
+            1 => '/usr/foobar/composer dump-autoload --no-scripts',
+            2 => 'rsync -e "ssh -p 22 -q -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no" -avz --exclude=.git --exclude=./var/cache/* --exclude=./var/log/* --exclude=./web/app_dev.php ./ tester@testhost:/var/www/test',
+        );
+
+        // Check total of Executed Commands
+        $this->assertEquals(count($testCase), count($ranCommands));
+
+        // Check Generated Commands
+        foreach ($testCase as $index => $command) {
+            $this->assertEquals($command, $ranCommands[$index]);
+        }
+
+        $this->assertEquals(0, $tester->getStatusCode());
+    }
+
     public function testInvalidTaskName()
     {
         $application = new MageApplicationMockup(__DIR__ . '/../../Resources/invalid-task.yml');
diff --git a/tests/Resources/composer-env.yml b/tests/Resources/composer-env.yml
new file mode 100644
index 0000000..2421fdf
--- /dev/null
+++ b/tests/Resources/composer-env.yml
@@ -0,0 +1,19 @@
+magephp:
+    log_dir: /tmp
+    composer:
+        path: /usr/bin/composer.phar
+    environments:
+        test:
+            composer:
+                path: /usr/foobar/composer
+            user: tester
+            host_path: /var/www/test
+            exclude:
+                - ./var/cache/*
+                - ./var/log/*
+                - ./web/app_dev.php
+            hosts:
+                - testhost
+            pre-deploy:
+                - composer/install: { flags: '--prefer-source' }
+                - composer/dump-autoload: { flags: '--no-scripts' }