A registered education savings plan (RESP) is a contract between an individual (the subscriber) and a person or organization (the promoter).
Under the contract, the subscriber names one or more children as beneficiaries and agrees to make contributions for them. The promoter agrees to pay Educational Assistance Payments (EAPs) to the beneficiaries at the point in time when they attend post-secondary education.
A contribution to a RESP isn't considered a tax deduction but there are government grants associated with certain contributions.
The concept of establishing an RESP is not so much a tax decision but an overall strategy to provide educational assistance to a child. The earlier the plan is established the longer investment income can accumulate and the more educational assistance is available to the beneficiaries (children).