Subletting vs Assigning a Lease: What Each Actually Means Legally

The core distinction between the two

Subletting and assigning a lease are two different legal arrangements that get used interchangeably in everyday conversation, but they work quite differently under the Residential Tenancies Act, 2006 (RTA), and the difference matters a great deal if something goes wrong. Both generally involve a tenant wanting someone else to occupy the rental unit, typically because the original tenant needs or wants to leave before the end of their tenancy. Where they differ is in whether the original tenant plans to come back, and in exactly who ends up legally responsible for the tenancy while someone else is living there.

Understanding this distinction clearly, before entering into either arrangement, tends to prevent a significant amount of confusion and risk down the line, particularly around who's actually on the hook if rent doesn't get paid or the unit is damaged.

Subletting: you keep your place in line

A sublet generally happens when a tenant temporarily lets someone else occupy their rental unit while intending to return before the end of the tenancy — a common example is a tenant leaving for a work assignment or extended travel for several months and arranging for someone else to live in and pay for the unit in the meantime. Under a sublet, the original tenant generally remains the tenant under the lease the whole time, and the person occupying the unit (the subtenant) generally doesn't acquire the same direct legal relationship with the landlord that the original tenant has.

Because the original tenant generally remains responsible throughout a sublet, they generally remain on the hook for the rent and the condition of the unit even while someone else is living there and dealing with the landlord day to day. This is one of the most important practical consequences of choosing a sublet over an assignment, and it's often overlooked by tenants focused mainly on finding someone to cover the rent while they're away.

Assigning: someone else steps into your shoes

An assignment, by contrast, generally involves the original tenant permanently transferring their tenancy to a new tenant, who then generally takes over the lease and becomes directly responsible to the landlord going forward. The original tenant isn't planning to return, and the goal is generally to exit the tenancy cleanly by having someone else formally take their place. Once an assignment is properly completed with the landlord's consent, the original tenant is generally released from further responsibility for the tenancy from that point forward.

This is often what a tenant actually wants when they say they're looking to "sublet" their apartment because they're moving away permanently and don't intend to come back — in that situation, an assignment is usually the legally accurate description of what they're trying to do, not a sublet, even though people often use the word "sublet" loosely to describe both.

Why landlord consent matters for both

Both subletting and assigning generally require the landlord's consent under the RTA — a tenant generally cannot unilaterally sublet or assign without the landlord's agreement, though a landlord generally cannot unreasonably withhold that consent either. This is a balance built into the Act: tenants generally have a right to request to sublet or assign, and landlords generally have a right to screen and approve (but not arbitrarily refuse) the proposed subtenant or new tenant.

In practice, this generally means a tenant wanting to sublet or assign should formally request the landlord's consent, typically providing information about the proposed subtenant or assignee so the landlord can reasonably evaluate the request, similar to how an original rental application might be evaluated.

What happens if a landlord refuses consent

If a landlord refuses consent to a proposed sublet or assignment, the tenant generally has some options depending on the circumstances, including potentially bringing the matter to the LTB if the refusal seems unreasonable rather than based on legitimate concerns about the proposed occupant. A landlord generally can't simply refuse every request as a blanket policy without considering the specific proposed subtenant or assignee on their merits — reasonable, individualized consideration is generally what the Act expects.

On the other side, a landlord with legitimate concerns about a proposed subtenant or assignee — for example, concerns about their ability to pay rent or a poor rental history — generally has a reasonable basis to decline, provided the refusal is genuinely connected to those concerns rather than an arbitrary or blanket policy.

Rent, liability, and who's on the hook

The liability consequences of the two arrangements differ significantly. Under a sublet, if the subtenant doesn't pay rent or damages the unit, the original tenant generally remains responsible to the landlord, since they remain the tenant of record throughout. Under a properly completed assignment, the new tenant generally becomes responsible going forward, and the original tenant is generally released, assuming the landlord's consent was properly obtained and the arrangement was genuinely an assignment rather than an informal, undocumented handoff.

This difference is exactly why it matters which arrangement is actually in place, rather than just what it's informally called — a tenant who believes they've "sublet" their unit and walked away from responsibility, when what actually happened (or what was actually agreed to) was a sublet rather than an assignment, can be in for an unpleasant surprise if something goes wrong with the subtenant down the line.

Why informal, undocumented arrangements cause problems

A considerable amount of difficulty in this area comes from informal handshake arrangements — a tenant letting a friend move in and take over payments without ever formally notifying the landlord or documenting whether it's a sublet or an assignment. Without the landlord's knowledge and consent, neither a sublet nor an assignment is generally properly completed, which can leave the original tenant unexpectedly on the hook, the occupying person without a clear legal relationship to the landlord, and the landlord potentially unaware of who's actually living in their unit.

Choosing the right option for your situation

For a tenant deciding between these options, the first and most important question is simply whether they intend to return to the unit. If yes, a sublet is generally the appropriate structure, with the understanding that responsibility for the tenancy generally stays with the original tenant throughout. If no, an assignment is generally the more appropriate path, provided the landlord consents and the transfer is properly documented. In either case, getting the landlord's consent in writing and clearly documenting which arrangement is actually being used tends to protect everyone involved far better than an informal understanding among friends or roommates.

It's also worth thinking ahead about what happens at the end of a fixed-term lease when a sublet or assignment is being considered partway through. A sublet that's set up to run right up to the end of the original tenant's lease term can raise questions about renewal and who's entitled to deal with the landlord about what happens next, so it's generally a good idea to clarify, in writing, what the plan is once the original lease term approaches its end — particularly whether the original tenant genuinely intends to return and resume occupying the unit, or whether the arrangement is likely to turn into something closer to a permanent transfer in practice.

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Reviewed by Ryan J. Manilla, BA, JD

Legal Reviewer · Landlord Tenant Ontario