A landlord, or landlady, is the owner of a house, apartment, condominium, or real estate which is rented or leased to an individual or business, who is called the tenant. 

In the United Kingdom the manager of a public house is also called the landlord or, more formally, as the licensed victualler. A female landlord can either be called a landlady or simply landlord. When a legal person is in the same position the term landlord is used. Other terms used are lessor and owner. The tenant can also be called a lesee or renter.

In the United States, landlord-tenant disputes are primarily governed by state law (not federal law) regarding property and contracts. State law and, in some places, city law or county law, sets the requirements for eviction of a tenant. Generally, there are a limited number of reasons for which a landlord can evict his tenant before the expiration of the tenancy, though at the end of the lease term the rental relationship can generally be terminated without giving any reason. Some cities have laws establishing the maximum rent a landlord can charge, known as rent control, and related just cause eviction controls.

A rental agreement, or lease, is the contract defining such terms as the price paid, penalties for late payments, the length of the rental or lease, and the amount of notice required before either the landlord or tenant cancels the agreement. In general, the landlord is responsible for repairs and maintenance, and the tenant is responsible for keeping the property clean and safe.

Many landlords hire a property management company to take care of all the details of renting their property out to a tenant. This usually includes advertising the property and showing it to prospective tenants, and then, once rented, collecting rent from the tenant and performing repairs as needed.

Sometimes the terms "slumlord" or "ghetto landlord" are used in reference to the owner of dilapidated buildings in blighted urban areas. As a result of declining demand and declining real estate prices, these landlords were often left with completely unprofitable properties and found themselves unable to pay for renovation and the regular maintanace of their property. The situation in many American slums became so dire that landlords were known to set their own buildings on fire in an attempt to collect on the insurance policy.