diff --git a/bin/gpm b/bin/gpm
index a19fea5d1..5a039e597 100755
--- a/bin/gpm
+++ b/bin/gpm
@@ -6,10 +6,17 @@ if (version_compare($ver = PHP_VERSION, $req = '5.4.0', '<')) {
     exit(sprintf("You are running PHP %s, but Grav needs at least PHP %s to run.\n", $ver, $req));
 }
 
+if (!file_exists(__DIR__ . '/../vendor')){
+    require_once __DIR__ . '/../system/src/Grav/Common/Composer.php';
+}
+
+use Grav\Common\Composer;
+
 if (!file_exists(__DIR__ . '/../vendor')){
     // Before we can even start, we need to run composer first
+    $composer = Composer::getComposerExecutor();
     echo "Preparing to install vendor dependencies...\n\n";
-    echo system('php bin/composer.phar --working-dir="'.__DIR__.'/../" --no-interaction --no-dev --prefer-dist -o install');
+    echo system($composer.' --working-dir="'.__DIR__.'/../" --no-interaction --no-dev --prefer-dist -o install');
     echo "\n\n";
 }
 
diff --git a/bin/grav b/bin/grav
index 1d31dd687..fb101b78f 100755
--- a/bin/grav
+++ b/bin/grav
@@ -6,10 +6,17 @@ if (version_compare($ver = PHP_VERSION, $req = '5.4.0', '<')) {
     exit(sprintf("You are running PHP %s, but Grav needs at least PHP %s to run.\n", $ver, $req));
 }
 
+if (!file_exists(__DIR__ . '/../vendor')){
+    require_once __DIR__ . '/../system/src/Grav/Common/Composer.php';
+}
+
+use Grav\Common\Composer;
+
 if (!file_exists(__DIR__ . '/../vendor')){
     // Before we can even start, we need to run composer first
+    $composer = Composer::getComposerExecutor();
     echo "Preparing to install vendor dependencies...\n\n";
-    echo system('php bin/composer.phar --working-dir="'.__DIR__.'/../" --no-interaction --no-dev --prefer-dist -o install');
+    echo system($composer.' --working-dir="'.__DIR__.'/../" --no-interaction --no-dev --prefer-dist -o install');
     echo "\n\n";
 }
 
diff --git a/system/src/Grav/Common/Composer.php b/system/src/Grav/Common/Composer.php
new file mode 100644
index 000000000..5efde8912
--- /dev/null
+++ b/system/src/Grav/Common/Composer.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace Grav\Common;
+
+/**
+ * Offers composer helper methods.
+ *
+ * @author  eschmar
+ * @license MIT
+ */
+class Composer
+{
+    /** @const Default composer location */
+    const DEFAULT_PATH = "bin/composer.phar";
+
+    /**
+     * Returns the location of composer.
+     *
+     * @return string
+     */
+    public static function getComposerLocation()
+    {
+        if (!function_exists('shell_exec') || strtolower(substr(PHP_OS, 0, 3)) === 'win') {
+            return self::DEFAULT_PATH;
+        }
+
+        // check for global composer install
+        $path = trim(shell_exec("command -v composer"));
+
+        // fall back to grav bundled composer
+        if (!$path || !preg_match('/(composer|composer\.phar)$/', $path)) {
+            $path = self::DEFAULT_PATH;
+        }
+
+        return $path;
+    }
+
+    public static function getComposerExecutor()
+    {
+        $executor = PHP_BINARY . ' ';
+        $composer = static::getComposerLocation();
+
+        if ($composer !== static::DEFAULT_PATH && is_executable($composer)) {
+            $file = fopen($composer, 'r');
+            $firstLine = fgets($file);
+            fclose($file);
+
+            if (!preg_match('/^#!.+php/i', $firstLine)) {
+                $executor = '';
+            }
+        }
+
+        return $executor . $composer;
+    }
+}
diff --git a/system/src/Grav/Console/ConsoleTrait.php b/system/src/Grav/Console/ConsoleTrait.php
index a2e80b6e8..233a5da79 100644
--- a/system/src/Grav/Console/ConsoleTrait.php
+++ b/system/src/Grav/Console/ConsoleTrait.php
@@ -2,6 +2,7 @@
 namespace Grav\Console;
 
 use Grav\Common\GravTrait;
+use Grav\Common\Composer;
 use Grav\Console\Cli\ClearCacheCommand;
 use Symfony\Component\Console\Formatter\OutputFormatterStyle;
 use Symfony\Component\Console\Input\ArrayInput;
@@ -85,7 +86,9 @@ trait ConsoleTrait
 
     public function composerUpdate($path, $action = 'install')
     {
-        return system('php bin/composer.phar --working-dir="'.$path.'" --no-interaction --no-dev --prefer-dist -o '. $action);
+        $composer = Composer::getComposerExecutor();
+
+        return system($composer . ' --working-dir="'.$path.'" --no-interaction --no-dev --prefer-dist -o '. $action);
     }
 
     /**