You are welcome to answer questions posted in the Ask a Teacher forum as long as your suggestions, help, and advice reflect a good understanding of the English language. If you are not a teacher, you will need to state that clearly at the top of your post. Please note, all posts are moderated by our in-house language experts, so make sure your suggestions, help, and advice house the kind of information an international language teacher would offer. If not, and your posts do not contribute to the topic in a positive way, they will be subject to deletion.
.
Allthough some purists still insist that 'in behalf of' means 'for the benefit of' and 'on behalf of' means 'as the representative of', usage shows that AmE uses both interchangeably while BrE generally uses 'on' for both meanings.
.
In BE we do favour 'on behalf of'. In fact, we favour it to excess; 'on behalf of' is widely used, I regret to have to report, in the unrelated meaning 'on the part of'.
(I wonder if 'in behalf of' will enjoy a resurgence, with people simply giving up on on - allowing the present abuse to become standard.)
On behalf of and In behalf of 
Re: On behalf of and In behalf of 
In BE we do favour 'on behalf of'. In fact, we favour it to excess; 'on behalf of' is widely used, I regret to have to report, in the unrelated meaning 'on the part of'.
Linear Mode
