Does a municipal fence bylaw or the provincial Line Fences Act apply to a dispute with my neighbour?

It genuinely depends on what the dispute is actually about, since the two operate alongside each other rather than one simply replacing the other. The Line Fences Act specifically addresses disagreements between neighbours over building, repairing, and cost-sharing for a shared boundary, or "line," fence — it's the tool for "who pays for this fence and how do we split it" type disputes.

A municipal fence by-law, by contrast, typically addresses different concerns entirely, things like maximum fence height, permitted materials, or mandatory pool enclosure requirements for safety, rules that apply regardless of who's paying or which neighbour benefits. A dispute about whether a fence is too tall, or doesn't meet a required pool safety standard, is more likely governed by a municipal by-law, while a dispute about whether a boundary fence needs to be built or repaired at all, and who pays, points to the Line Fences Act instead.

Because both can potentially apply to the same physical fence for different reasons, it's worth checking your specific municipality's by-laws alongside the Line Fences Act, and getting legal advice if your situation seems to raise both kinds of issues at once.