Do all named executors have to agree before an estate decision can be made in Ontario?

As a general default, yes — where a will names more than one executor and doesn't say otherwise, they're generally expected to act unanimously on estate decisions. Executors hold their authority jointly, and the usual rule is that important decisions, like selling estate property, making distributions, or signing off on the accounts, need agreement from all of them rather than just one acting alone on behalf of everyone.

This default exists to protect beneficiaries from one trustee acting unilaterally in a way the others might not have agreed to, but it's also exactly what creates deadlock problems when co-executors genuinely can't agree. A will can change this default by expressly allowing decisions to proceed on a majority basis, or by assigning specific tasks to specific named executors, but without that kind of language, unanimity is what courts generally expect.

Because the unanimity expectation is the default rather than an absolute rule that applies identically in every will, anyone administering an estate with co-executors should check the will's actual wording carefully rather than assuming, and get advice early if it looks like agreement on a needed decision may be hard to reach.