diff --git a/config/environment.php b/config/environment.php
index 8a30037c5..bbc43952a 100644
--- a/config/environment.php
+++ b/config/environment.php
@@ -3,4 +3,7 @@
 /*----------------------------------------------------*/
 // Define environment type
 /*----------------------------------------------------*/
-return '';
+return [
+    'local' => 'INSERT-HOSTNAME',
+    'production' => 'INSERT-HOSTNAME'
+];
diff --git a/library/Thms/Config/Environment.php b/library/Thms/Config/Environment.php
index 48ed3bbf7..186b923b2 100644
--- a/library/Thms/Config/Environment.php
+++ b/library/Thms/Config/Environment.php
@@ -44,9 +44,23 @@ public function which($hostname = '')
         // by comparing the given hostnames from an array.
         if (is_array($this->locations) && !empty($this->locations)) {
             foreach ($this->locations as $location => $host) {
-                $host = is_array($host) ? $host : [$host];
-                if (in_array($hostname, $host)) {
-                    return $location;
+
+                /*
+                 * Test against an array of hosts.
+                 */
+                if (is_array($host)) {
+                    if (in_array($hostname, $host)) {
+                        return $location;
+                    }
+                } else {
+                    /*
+                     * Test against a string/regular expression.
+                     */
+                    $pattern = ($host !== '/') ? str_replace('*', '(.*)', $host).'\z' : '^/$';
+
+                    if ((bool) preg_match('/'.$pattern.'/', $hostname)) {
+                        return $location;
+                    }
                 }
             }
         }
@@ -54,6 +68,8 @@ public function which($hostname = '')
         // If not using array, a single string is provided to define the
         // environment.
         if (is_string($this->locations)) {
+
+            // Default string.
             return $this->locations;
         }
 
diff --git a/tests/config/EnvironmentTest.php b/tests/config/EnvironmentTest.php
index e5996b61d..b2e101b26 100644
--- a/tests/config/EnvironmentTest.php
+++ b/tests/config/EnvironmentTest.php
@@ -61,4 +61,26 @@ public function testWhichEnvironmentWithString()
         $env = new \Thms\Config\Environment($locations);
         $this->assertEquals('local', $env->which());
     }
+
+    public function testWhichEnvironmentWithRegEx()
+    {
+        $locations = [
+            'local' => '*.themosis.dev',
+            'production' => '*.aws.elastic456278s9d.com',
+            'staging' => 'xyz\..+\.net',
+            'custom' => 'my-hostname',
+        ];
+
+        $env = new Thms\Config\Environment($locations);
+
+        $this->assertEquals('local', $env->which('server001.themosis.dev'));
+        $this->assertEquals('local', $env->which('abcserver3578sdd67.themosis.dev'));
+
+        $this->assertEquals('production', $env->which('us2-467.aws.elastic456278s9d.com'));
+
+        $this->assertEquals('staging', $env->which('xyz.some-name.net'));
+        $this->assertEquals('staging', $env->which('xyz.another_name215658.net'));
+
+        $this->assertEquals('custom', $env->which('my-hostname'));
+    }
 }