A landlord is the owner of property such as a farm, house, apartment, condominium, land, or real estate that is rented or leased to an individual or business, known as a tenant (also called a lessee or renter). The term landlord applies when a juristic person occupies this position. Alternative terms include lessor and owner. For female property owners, the term landlady may be used. In the United Kingdom, the manager of a pub, officially a licensed victualler, is also referred to as the landlord/landlady. In political economy, landlord specifically refers to someone who owns natural resources (such as land, excluding buildings) from which they derive economic rent, a form of passive income.

The concept of a landlord can be traced to the feudal system of manoralism (seignorialism), where landed estates were owned by Lords of the Manor (mesne lords). These lords were typically members of the lower nobility who later formed the rank of knights during the high medieval period. They held their fiefs through subinfeudation, though in some cases land was directly subject to members of higher nobility, such as the royal domain owned directly by a king, or the Holy Roman Empire's imperial villages which were directly subject to the emperor. This medieval system evolved from the villas and latifundia (large, peasant-worked farmsteads) of the Roman Empire. In modern times, the term "landlord" refers to a property owner who charges rent to a tenant.

A rental agreement, or lease, is the contract that defines the terms of a rental arrangement. These terms include the rental price, penalties for late payments, the duration of the rental or lease, and the notice period required before either party can cancel the agreement. Generally, responsibilities are divided as follows: homeowners handle repairs and property maintenance, while tenants keep the property clean and safe.

Many property owners hire property management companies to manage rental details. These companies typically advertise the property, show it to potential tenants, negotiate and prepare written leases or licence agreements, collect rent, and perform necessary repairs.

In the United States, residential landlord-tenant disputes are primarily governed by state law rather than federal law, particularly regarding property and contracts. State laws, and sometimes city or county laws, establish the requirements for eviction. Generally, landlords can only evict tenants before a lease expires for specific legally valid reasons, though they can typically end the rental relationship without giving a reason when the lease term concludes. Some jurisdictions have enacted rent control or rent regulation laws that limit how much landlords can charge. There is also an implied warranty of habitability that requires landlords to maintain safe, decent, and habitable housing with basic safety features like smoke detectors and secure doors. Most common disputes arise from either the landlord failing to provide services or the tenant failing to pay rent—with service issues sometimes leading to payment problems. As typically explained in the lease, withholding rent constitutes justifiable grounds for eviction. City ordinances can also influence rental policies, such as the increasing adoption of source-of-income anti-discrimination rules. Tenants unions can also affect housing policy through political organization.

In Canada, residential homeowner–tenant disputes are primarily governed by provincial law regarding property and contracts. Provincial law sets the requirements for eviction of a tenant. Generally, there are a limited number of reasons for which a landlord can evict a tenant. Some provinces have laws establishing the maximum rent a landlord can charge, known as rent control, or rent regulation, and related eviction. There is also an implied warranty of habitability, whereby a landlord must maintain safe, decent and habitable housing, meeting minimum safety requirements.

Private sector renting is largely governed by many of the Landlord and Tenant Acts, in particular the Landlord and Tenant Act 1985 which sets bare minimum standards in tenants' rights against their landlords. Another key statute is the Housing Act 2004. Rents can be freely increased at the end of a usual six-month duration, on proper notice given to the tenant. A Possession Order under the most common type, the assured shorthold tenancy (AST) is usually obtainable after eight weeks/two months of unpaid rent, and at the court's discretion after serving the tenant with a Section 8 notice (under the Housing Act 1988 as amended) for a lesser period for all assured tenancies, and on other grounds which defer to the landlord's ownership of the property. If the tenancy is an AST then any possession order will not take effect until six months has passed into the initial tenancy. A tenancy of someone who has been in occupation since before 15 January 1989 usually, if not a shorthold from the outset following their inception from 1980 onwards, may be a "regulated tenancy" with many more rights, especially under the Rent Act 1977 and Protection from Eviction Act 1977, introduced by the Third Wilson ministry.

Each house in multiple occupation, a unit the law does not regard it as a single household having more than three tenants, is subject to enhanced regulations including the Housing Act 2004. A council-issued licence to be a landlord of such a unit is always required in some local authorities (in others, limited to the larger statutory examples).