Sublease vs Assignment: What Is the Difference?

The difference between a sublease and an assignment comes down to one question: who stays on the hook for the lease. Both arrangements bring a new person into a rental that someone else originally signed for, but they divide responsibility in opposite ways. Choosing the wrong one can leave a departing tenant liable for rent long after moving out, so it is worth understanding the distinction before you sign anything.

This guide keeps the explanation general rather than tied to one state, since the basic concepts hold true across the country. The specific rules and any required procedures vary by state and by lease, so always check your own agreement and your state law before acting. If you are weighing one option against the other, the differences below will point you to the right choice.

What a Sublease Does

In a sublease, the original tenant stays in the picture as a middle party. The original tenant signs a new agreement with a subtenant, who moves in and typically pays rent to the original tenant. The original tenant then continues to pay the landlord under the main lease. Think of it as a chain: the landlord deals with the original tenant, and the original tenant deals with the subtenant.

The key feature of a sublease is that the original tenant remains fully liable to the landlord. If the subtenant stops paying or damages the unit, the landlord looks to the original tenant, not the subtenant, for the rent and the repairs. The original tenant has simply added a person beneath them in the chain. This makes a sublease the right tool when a tenant plans to return, such as during a summer away or a temporary work assignment, or when the lease has only a few months left.

What an Assignment Does

An assignment works differently. Instead of adding a person beneath them, the original tenant transfers the entire lease to a new tenant, called the assignee. The assignee steps into the original tenant shoes and takes on the lease directly with the landlord. There is no middle party. The original tenant exits, and the new tenant becomes the tenant of record going forward.

An assignment is the cleaner exit when a tenant needs to leave for good and does not plan to return. Because the assignee deals with the landlord directly, the assignee pays rent to the landlord and answers to the landlord for the condition of the unit.

One detail often gets overlooked in an assignment: the security deposit. Because the assignee is taking over the lease, the parties must decide what happens to the deposit the original tenant paid. Sometimes the original tenant is refunded and the assignee posts a fresh deposit, and sometimes the deposit transfers with the lease. Settle this in writing at the time of the assignment so no one argues later about who is owed the money at the end of the term.

Who Is Liable in Each

Liability is where the two arrangements truly part ways. In a sublease, the original tenant stays liable. The landlord can pursue the original tenant for any default by the subtenant. In an assignment, the assignee becomes the responsible party for obligations going forward.

One important caveat protects landlords. In many situations, an assignment does not automatically release the original tenant from liability unless the landlord agrees to that release in writing. Without a written release, sometimes called a novation, the landlord may still be able to hold the original tenant responsible if the assignee defaults. A departing tenant who wants a clean break should ask for that release in writing rather than assume the assignment alone ends their obligations.

When Landlord Consent Is Required

Most leases require the landlord written consent before either a sublease or an assignment. The exact rule depends on the lease language and on state law. Some states give tenants in certain buildings a statutory right to sublease with consent that may not be unreasonably withheld, as New York does for many buildings under its sublease statute. You can read how that works on the New York sublease page. Other states leave the matter entirely to the lease.

The safe practice in every case is to get the landlord written consent before moving anyone in. Doing it informally invites a dispute and can put the original tenant in breach of the lease. Subletting or assigning without permission gives the landlord a reason to act against you, so put the consent in writing every time.

Read your lease for the exact wording. Some leases flatly prohibit subletting and assignment, some allow it only with consent, and some say consent may not be unreasonably withheld. The phrasing controls how much room you have. If the lease is silent, your state default rule fills the gap, and that default varies widely from one state to the next. When the stakes are high, a short conversation with a local attorney is cheaper than a wrongful eviction.

Which One Should You Use

The choice usually follows from your plans. If you intend to come back, or the lease has only a short time remaining, a sublease keeps you in control and lets you reclaim the unit later. If you are leaving permanently and want out of the obligation, an assignment paired with a written release from the landlord gives you the cleanest exit. Either way, start from a proper written document rather than a handshake. You can find the right starting forms on the lease agreement page.

For landlords, the distinction matters just as much. A sublease keeps your original tenant on the hook, which is often the safer position. An assignment changes who you can pursue, so review the new tenant carefully and decide deliberately whether to release the original tenant. In both cases, a clear written agreement protects everyone involved.

One last point applies to both sides. The labels people use are not always accurate. Some agreements titled as a sublease actually function as an assignment, and the reverse happens too. What controls is not the heading but the substance: does the original tenant stay liable and keep a stake in the lease, or does the new tenant take over entirely. When you read or draft one of these agreements, look past the title and trace where the liability lands. That is the question that decides which arrangement you really have.