Can co-executors act on a majority basis, or must every decision be unanimous in Ontario?

Not unless the will says so. The general default in Ontario is that co-executors must act unanimously — every one of them needs to agree before a major estate decision is carried out — rather than being able to outvote each other the way a board of directors might. This can come as a surprise to people who assume "majority rules" applies the same way it does in other group decision-making contexts.

A will can override this default by expressly stating that a majority of the named executors can make decisions, or by giving different executors authority over different specific tasks or assets. Where a will includes that kind of language, it generally controls, and the executors can proceed on a majority basis for the situations it covers. Without it, unanimity remains the expectation, and a lone dissenting co-executor can effectively block a decision even if outnumbered.

This is one of the more practical reasons testators are encouraged to think carefully about naming multiple executors together, and to consider whether majority-decision language, staggered responsibilities, or a single executor with an alternate might work better for their particular family and estate.