Does getting married cancel my existing will in Ontario?

Yes. In Ontario, getting married automatically revokes any will you made before the marriage, unless the will was made specifically in contemplation of that marriage and says so clearly. This rule is found in Ontario's Succession Law Reform Act.

What this means in practice: if you made a will before you got married — perhaps leaving assets to children from a prior relationship — and you then marry without making a new will, you die intestate (without a valid will). Your estate is then distributed under the intestacy rules, which may produce a very different outcome than you intended.

For blended families, this is a common and serious trap. Someone may have carefully planned their estate before a second marriage, naming their children as beneficiaries, only to have the marriage wipe out that will entirely. The new spouse then has strong intestacy rights that can significantly reduce what the children receive.

The solution is straightforward: make a new will either before or very soon after your marriage. If you are making a will before the wedding specifically because you want it to survive the marriage, it must explicitly state that it is made in contemplation of your upcoming marriage to a named person. A lawyer can make sure that language is included correctly.