Can you build a triplex in Ontario, or a fourplex in Toronto? Yes to both.

Up to three. Under Bill 23, the More Homes Built Faster Act, 2022, most residential lots in Ontario that already hold one home can add a second and a third unit as-of-right. "As-of-right" means you do not need a rezoning, a minor variance, or a council vote for those units. If your plans meet the zoning rules, the city must approve them. This three-unit floor applies province-wide and is the minimum every Ontario municipality has to allow. A city can permit more than three, but it cannot allow fewer.

Yes, anywhere in the city. Since Toronto adopted its citywide multiplex bylaw on May 10, 2023, up to four units (a fourplex) are allowed as-of-right on residential lots across the whole city. This sits one unit above Ontario's three-unit floor. You still have to meet the building rules (height, setbacks, lot coverage, floor area, and so on), but you do not need a rezoning or a public hearing for the fourth unit itself. The practical limit on most lots is the building size the zoning allows, not the unit count.

Bill 23 is the provincial law and Toronto's bylaw is the city rule that goes further. Bill 23 sets the province-wide floor of three units. Toronto's multiplex bylaw stacks a fourth unit on top of that floor, citywide. So think of it as two layers: the province guarantees three units everywhere in Ontario, and Toronto adds a fourth on its own lots. In parts of Toronto the city has added even more, but the three-unit provincial floor is what every Ontario town shares.

Only partly. In June 2025 council voted to allow sixplexes (up to six units) as-of-right, but only in nine wards, plus a pilot in Scarborough North, not across the whole city. The nine wards are mostly downtown and in the east end. The rest of the city is still capped at four units unless that ward's councillor asks to opt in. Council did not reject sixplexes outright; it made them local instead of citywide, which is what led to the federal funding cut.

Nine wards, plus a Scarborough North pilot. Based on the June 2025 vote, sixplexes are allowed as-of-right in Ward 4 (Parkdale–High Park), Ward 9 (Davenport), Ward 10 (Spadina–Fort York), Ward 11 (University–Rosedale), Ward 12 (Toronto–St. Paul's), Ward 13 (Toronto Centre), Ward 14 (Toronto–Danforth), Ward 19 (Beaches–East York), and a pilot area in Ward 23 (Scarborough North). Other wards can be added later if their councillor opts in. If your lot is outside these areas, the citywide fourplex rule still applies, so you can still build up to four units.

Because a citywide sixplex rule was a condition of the federal deal, and Toronto did not deliver it. In 2023 Toronto signed a four-year, $471 million agreement with the federal Housing Accelerator Fund. One of the promises was to legalize sixplexes across the whole city. When council limited them to nine wards in June 2025, Ottawa treated that as not meeting the condition. In January 2026 the federal government cut Toronto's funding by $10 million. Toronto still receives $461 million, and the money could be restored if more wards opt in.

Building is up, but from a low base. City Hall Watcher, reading the city's own planning data, counted 393 new multiplex units given building permits in the first 18 months of the citywide rule (May 2023 to November 2024). The yearly number of multiplex permits more than tripled from 2022 to 2024. That is real growth, but it is still below the 600 to 3,000 units a year the city's own housing plan said the reform could produce by 2031. So the rule is working, just slower than hoped.

Generally no. Toronto removed minimum parking requirements across the city in 2021, before the multiplex bylaw. That means a new fourplex or triplex does not have to provide a set number of off-street parking spaces. You can still build parking if you or your tenants want it, but the city no longer forces it. Removing that requirement frees up lot space and can lower build cost, which matters most on narrow lots where a required parking pad would have crowded out a unit.

The second and third units do not. Bill 23 exempts units 2 and 3 from development charges and from parkland dedication fees. This is one of the most valuable parts of the law for a small builder, because development charges can add tens of thousands of dollars per unit. The exemption does not automatically cover a fourth unit, so in Toronto the fourth unit may still be charged depending on the local rules. Always confirm the fee treatment for your specific project with the city before you budget.

Because the fee cuts left them short of money for roads, water, and sewers. Development charges are how cities pay for the infrastructure that new housing needs. When Bill 23 waived those charges on the second and third units, cities said they would have to cover the gap another way, usually from property taxes or by delaying projects. The Association of Municipalities of Ontario estimated the fee cuts could cost the province's 29 largest cities up to $1 billion a year between 2023 and 2031. The province promised to make cities "whole," and that debate is still going.

It applies to most residential lots, not literally every one. The three-unit floor covers lots with an existing detached house, semi-detached house, or rowhouse, in most residential areas. There are limits: the units still have to meet servicing rules (water and sewer), building code, and the shape rules in the local zoning bylaw. Some lots, for example very small ones or those with servicing problems, may not physically fit three units even though the law allows them. The law removes the zoning barrier; it does not remove the physical and engineering ones.

It is a useful case study with a clear warning. The good part: a three-unit floor across a whole province, plus a big city adding a fourth citywide, is a strong base for gentle density. The warning part is what happened with sixplexes. Even with $471 million of federal money on the line, Toronto council chose to limit sixplexes to nine wards rather than the whole city, and accepted a $10 million cut rather than go citywide. The lesson is that legal power at the province level does not guarantee a city will use all of it. Local politics still sets the real ceiling.