How to theme a field group (with div output and css class set)? I would like to theme a group of fields that belong to a content type. For example to position all of them at a certain area in the page.

I want to do this in conjunction with the field_group module

I know that it is possible to theme an individual field, by overriding field.tpl.php in your own theme, along with CSS as required. And I have done this successfully.

However I'd like to know if there is something like field-group.tpl.php which I can override in my own theme, similar to how I have done for field.tpl.php.

When editing the field group settings in the Content Type, &lt;div&gt; can be specified for a field group, as well as CSS classes. So I create a field group and specify these things and then add some fields to belong to my field group. However, when I look at the html source output for content of this content type, I cannot see anywhere this extra div is defined nor its groupname. Therefore I don't know how to theme it. Please advise.
I know you mentioned wanting to use the field_group module, but I don't immediately see the need.

If the goal is to position a set of fields all together, why not override your node.tpl.php file, calling it node--my-content-type.tpl.php and then somewhere within it do something along the lines of:

&lt;div id="field-group"&gt;
  &lt;?php print render($content['my_field1']); ?&gt;
  &lt;?php print render($content['my_field2']); ?&gt;
  &lt;?php print render($content['my_field2']); ?&gt;
&lt;/div&gt;


That way they can A) be positioned by positioning #field-group, as well as allowing you to theme each field in their own field.tpl.php file.