Can a will validity dispute be resolved by summary judgment instead of a full trial in Ontario?

Sometimes, yes. Where the evidence on a will challenge is largely documentary, undisputed, or otherwise capable of being fairly assessed without the need for a full trial with live witnesses, a party can bring a motion for summary judgment, asking an Ontario judge to decide the will's validity based on the written record rather than proceeding to a proof-in-solemn-form trial. This can save significant time and cost where the case genuinely doesn't need live testimony to be fairly resolved.

Summary judgment is less likely to succeed, though, where the case turns heavily on credibility — for example, where the outcome depends on weighing conflicting accounts about the testator's capacity or what happened when instructions were given, which usually calls for a judge to see and hear witnesses directly. Courts are cautious about deciding a will's validity, which permanently affects an estate and its beneficiaries, on a paper record alone unless they're genuinely satisfied a fair and just determination can be made that way. Because whether a case is suitable for summary judgment depends heavily on the specific evidence available, get advice early on whether pursuing this route makes sense for your dispute rather than assuming a full trial is inevitable, or that a shortcut is available.