Can my separated (but not divorced) spouse inherit if I die without a will in Ontario?

Often not — and this changed on January 1, 2022. Under the Succession Law Reform Act as amended, a separated spouse is treated as having died before you for intestacy purposes, so they do not inherit, even though the marriage has not been legally ended. Before 2022 the opposite was true: only a final divorce removed a spouse's entitlement, and a long-separated spouse could still inherit the whole estate.

The separation has to meet the statute's test, not just feel final. It is met if you were living separate and apart because of the breakdown of the marriage for three years or more when you died, or if you had a valid separation agreement, a family arbitration award, or a court order settling your affairs. If none of those applies — you separated recently and signed nothing — your spouse may still inherit as a spouse.

That gap is exactly why separating and doing nothing is risky. A will removes the guesswork. Note a separated spouse may still bring a dependant's support claim against your estate regardless.