Is Toronto's municipal vacant home tax the same thing as the federal Underused Housing Tax?

No, they're two completely separate taxes, and mixing them up is a common and costly mistake. Toronto's vacant home tax is a municipal levy passed under the city's own bylaw powers, aimed broadly at any residential property in Toronto that sits vacant, regardless of who owns it. The federal Underused Housing Tax, under the federal Underused Housing Tax Act, is a distinct national tax aimed primarily at non-resident, non-Canadian owners of vacant or underused residential property in Canada.

Because both taxes use similar language - "vacant," "underused," "residential property" - and both can apply to the same property in the same year, it's easy to assume complying with one satisfies the other. It doesn't. You can owe Toronto's municipal tax, the federal tax, both, or neither, depending entirely on the specific rules of each program and who owns the property, and each has its own separate declaration and filing process that has to be done independently. Ottawa has a similar municipal vacant home tax program running alongside the federal tax as well. Given how easy these are to confuse, it's worth checking both requirements separately for any property that might be vacant or underused.