You can form a contract with a child but the real question is whether you willbe able to enforce it. The answer to that depends to some extenton the State in Australia where the contract is formed. For example, in some States (and again this depends on the circumstances)the child might have the choice of eitherwithdrawing from the contract without penaltyafter signing it,or enforcing the contractagainst the other party. The other party does not have the same flexibility. If this question is important to your business or to the financial or other wellbeing of the child, it would be a good idea to get legal advice before entering into the contract, as the rules vary considerably from State to State.