Wrapping div around form function gng_unsubscribe_form($form,&amp;$form_state) {
 $form['email'] = array(
 '#title' =&gt; 'Email',

'#type' =&gt; 'textfield',
 );
 $form['submit']=array(
 '#type'=&gt;'submit',
 '#value'=&gt;t('Unsubscribe'),
 '#prefix' =&gt; '&lt;div class="btn-area"&gt;',
 '#suffix' =&gt; '&lt;/div&gt;'
 );
 return $form;
 }


For a particular field I can add custom class using #prefix and #suffix, is there a way to add wrapping div around whole form?
According to the Form API Reference, #prefix &amp; #suffix are valid properties of the form element, so you should be able to:

$form['#prefix'] = '&lt;div class="some-class"&gt;';
$form['#suffix'] = '&lt;/div&gt;';