A public utility company (usually just utility) is an organization that maintains the infrastructure for a public service (often also providing a service using that infrastructure). Public utilities are subject to forms of public control and regulation ranging from local community-based groups to statewide government monopolies.

Public utilities are meant to supply goods/services that are considered essential; water, gas, electricity, telephone, and other communication systems represent much of the public utility market. The transmission lines used in the transportation of electricity, or natural gas pipelines, have natural monopoly characteristics. If the infrastructure already exists in a given area, minimal benefit is gained through competing. In other words, these industries are characterized by economies of scale in production.

There are many different types of public utilities. Some, especially large companies, offer multiple products, such as electricity and natural gas. Other companies specialize in one specific product, such as water. Modern public utilities may also be partially (or completely) sourced from clean and renewable energy in order to produce sustainable electricity. Of these, wind turbines and solar panels are those used most frequently.