diff --git a/src/Commando/Command.php b/src/Commando/Command.php
index 40a5829..21fafcc 100755
--- a/src/Commando/Command.php
+++ b/src/Commando/Command.php
@@ -70,6 +70,7 @@ class Command implements \ArrayAccess, \Iterator
         // mustBeNumeric
         // mustBeInt
         // mustBeFloat
+        'needs' => 'needs',
 
         'file' => 'file',
         'expectsFile' => 'file',
@@ -205,6 +206,18 @@ private function _require(Option $option, $require = true)
         return $option->setRequired($require);
     }
 
+    /**
+     * Set a requirement on an option
+     *
+     * @param \Commando\Option $option Current option
+     * @param string $name Name of option
+     * @return \Commando\Option instance
+     */
+    private function _needs(Option $option, $name)
+    {
+        return $option->setNeeds($name);
+    }
+
     /**
      * @param Option $option
      * @param string $alias
@@ -353,6 +366,17 @@ public function parse()
                     }
                 }
             }
+
+            // See if our options have what they require
+            foreach ($this->options as $option) {
+                $needs = $option->hasNeeds($this->options);
+                if ($needs !== true) {
+                    throw new \InvalidArgumentException(
+                        'Option "'.$option->getName().'" does not have required option(s): '.implode(', ', $needs)
+                    );
+                }
+            }
+
             // Set values (validates and performs map when applicable)
             foreach ($keyvals as $key => $value) {
 
diff --git a/src/Commando/Option.php b/src/Commando/Option.php
index 9832226..5c1baa5 100755
--- a/src/Commando/Option.php
+++ b/src/Commando/Option.php
@@ -11,6 +11,7 @@ class Option
         $value = null, /* mixed */
         $description, /* string */
         $required = false, /* bool */
+        $needs = array(), /* set of other required options for this option */
         $boolean = false, /* bool */
         $type = 0, /* int see constants */
         $rule, /* closure */
@@ -119,6 +120,22 @@ public function setRequired($bool = true)
         return $this;
     }
 
+    /**
+     * Set an option as required
+     *
+     * @param string $option Option name
+     */
+    public function setNeeds($option)
+    {
+        if (!is_array($option)) {
+            $option = array($option);
+        }
+        foreach ($option as $opt) {
+            $this->needs[] = $opt;
+        }
+        return $this;
+    }
+
     /**
      * @param mixed $value default value
      * @return Option
@@ -241,6 +258,15 @@ public function getAliases()
         return $this->aliases;
     }
 
+    /**
+     * Get the current set of this option's requirements
+     * @return array List of required options
+     */
+    public function getNeeds()
+    {
+        return $this->needs;
+    }
+
     /**
      * @return bool is this option a boolean
      */
@@ -266,6 +292,27 @@ public function isRequired()
         return $this->required;
     }
 
+    /**
+     * Check to see if requirements list for option are met
+     *
+     * @param array $optionsList Set of current options defined
+     * @return boolean|array True if requirements met, array if not found
+     */
+    public function hasNeeds($optionsList)
+    {
+        $needs = $this->getNeeds();
+
+        $definedOptions = array_keys($optionsList);
+        $notFound = array();
+        foreach ($needs as $need) {
+            if (!in_array($need, $definedOptions)) {
+                $notFound[] = $need;
+            }
+        }
+        return (empty($notFound)) ? true : $notFound;
+
+    }
+
     /**
      * @param mixed value for this option (set on the command line)
      */
diff --git a/tests/Commando/CommandTest.php b/tests/Commando/CommandTest.php
index 0ab15db..08851ce 100755
--- a/tests/Commando/CommandTest.php
+++ b/tests/Commando/CommandTest.php
@@ -152,4 +152,34 @@ public function testGetValues()
         $this->assertEquals(array('a' => 'v1', 'b' => 'v2'), $cmd->getFlagValues());
     }
 
+    /**
+     * Ensure that requirements are resolved correctly
+     */
+    public function testRequirementsOnOptionsValid()
+    {
+        $tokens = array('filename', '-a', 'v1', '-b', 'v2');
+        $cmd = new Command($tokens);
+
+        $cmd->option('b');
+        $cmd->option('a')
+            ->needs('b');
+
+        $this->assertEquals($cmd['a'], 'v1');
+    }
+
+    /**
+     * Test that an exception is thrown when an option isn't set
+     * @expectedException \InvalidArgumentException
+     */
+    public function testRequirementsOnOptionsMissing()
+    {
+        $tokens = array('filename', '-a', 'v1');
+        $cmd = new Command($tokens);
+
+        $cmd->trapErrors(false)
+            ->beepOnError(false);
+        $cmd->option('a')
+        ->needs('b');
+    }
+
 }
\ No newline at end of file
diff --git a/tests/Commando/OptionTest.php b/tests/Commando/OptionTest.php
index 8eddb47..a04b9e3 100644
--- a/tests/Commando/OptionTest.php
+++ b/tests/Commando/OptionTest.php
@@ -131,6 +131,31 @@ public function testDefault($val)
         $this->assertEquals($val, $option->getValue());
     }
 
+    /**
+     * Test that requires options are set correctly
+     */
+    public function testSetRequired()
+    {
+        $option = new Option('f');
+        $option->setNeeds('foo');
+
+        $this->assertTrue(in_array('foo', $option->getNeeds()));
+    }
+
+    /**
+     * Test that the needed requirements are met
+     */
+    public function testOptionRequirementsMet()
+    {
+        $option = new Option('f');
+        $option->setNeeds('foo');
+        $optionSet = array(
+            'foo' => new Option('foo')
+        );
+
+        $this->assertTrue($option->hasNeeds($optionSet));
+    }
+
     // Providers
 
     public function values()