In behalf of or On behalf of difference

Similar expressions, but they have a slightly different meaning.

On behalf of someone 
in the name of someone (representing someone)

Example:

• Don’t worry on my behalf. (instead of me)
• I am proud to accept this award on behalf of Georgina who is unable to be with us today. (that means ..I accepted an award for her because she could not make it to the ceremony but I”ll give it to her)

(related to contract)

This

is quite an important phrase to know. If someone does something on behalf of something or someone else, they do it for them and as if they were the person involved in the contract.

This is often used for people that have mental illness or that are physically ill in a way that means they cannot reliably sign a contract. In other circumstances, a legal representative will be allowed to sign something for their client as long as they have permission to do so.

Businessmen and women can also sign documents on behalf of a whole company or an organisation. They are the managers so they get to handle this responsibility and it is up to them to read the document throughly to check all of the clauses.

In behalf of someone 
to favour someone (to benefit /for the benefit of /in order to help someone)

Example:

• We raised money in behalf of the orphans. (for the orphans)
  See both in the same sentence.
• They are collecting on behalf of (representing) the charity which is seeking funds in behalf of (to favour) its cause.

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