A broadcast license (U.S.) or broadcast licence (elsewhere) is a specific type of spectrum license that grants the licensee the privilege to use a portion of the radio frequency spectrum in a given geographical area for broadcasting purposes. The licenses are generally straddled with additional restrictions that vary from band to band. In some cases, the FCC does not assign licenses to any exclusive user, but allows qualified users to obtain a license  The Radio Act of 1927 established the regulatory premise that persists to this day: the spectrum belongs to the public and that licensees have no property rights to continue using it. Although the spectrum is licensed to bidders, the purchase does not represent ownership or rights, only privileges to using that part of the spectrum.
The spectrum can be divided differently, depending on what it will be used for. As indicated in the graph by the National Telecommunications and Information Administration (NTIA), the frequency allocation can be represented by different types of services that vary in size. There are many available options when getting a broadcast license, even options the FCC recognizes as being necessary. It sometimes moves further to determine how much spectrum to allot to particular licensees within a given band (blocks of 10 kHz). The amount of spectrum allotted to a given licensee is a function of whatever bandwidth the FCC concludes is needed for the service in question.
Licensing is also different for public radio and public television, and for community radio and community television, as compared to commercial applicants and licensees. Licensees also have to be aware of important dates from the point of needing a license to renewing it. The FCC has dates depending on the type of service that certain requirements are due. This includes radio and television services and vary by state. These requirements include the expiration of the license, the filing date for renewals and other steps that may be necessary for a licensee.
Licensing is performed by a government agency (the broadcasting authority), providing a mechanism both for managing the limited resource of radio frequency spectrum and for implementing prevailing public policy, such as policies regarding concentration of media ownership. The determination of which frequencies can be used by various licensees is done through a frequency allocation process, which in the United States is further specified by the Federal Communications Commission (FCC) in a table of allotments. In the United States, the FCC is authorized to regulate the access to the spectrum for private uses and state and local governmental uses. But it is the National Telecommunications and Information Administration under the Commerce Department to allocate spectrum for use by the federal government, including the military. This means when there is a re-allocation of spectrum.
In some cases (e.g., CB radio), the public may use the spectrum without a need of a license. Generally, for commercial use of the spectrum (such as television, AM/FM radio, and some types of two-way communications), the FCC will assign portions of the spectrum to particular licensees. This is called assignment. An assigned portion may be a single frequency, or a wide band of frequencies. In the issuing of broadcast licenses, the FCC relies on "comparative hearings", whereby the most qualified user will get use of the spectrum in order to best serve the public interest. However, some researchers have pointed out that the procedure favors entrenched incumbents.
Management of technical specifications, such as those implemented in broadcast television systems, is normally undertaken as a part of broadcast licensing in each country. Various radio bands carry different radio signals, such as video and audio, digital and analog, narrowband and broadband, and different types of content, and are therefore licensed differently.
Violation of the terms of a license, either due to technical fault or illegal content, may result in fines, or rarely even revocation of the license. Licenses have also been threatened by a lack of honesty on the part of the holder, or the failure to keep a public file (U.S. and Canada).
Unlicensed broadcasting refers both to legal devices allowed to transmit at low power without a license, and pirate stations which violate the law, often because of insurmountable legal restrictions on getting a license.
Originally, broadcast licenses were issued for only a nominal payment, but work by economist Ronald Coase challenged FCC's micromanagement approach. Coase proposed that just as other valuable resources (land, metal, etc.) free market could regulate the use of radio spectrum. This proposition is based on the assumption of Coase theorem, that is, with well-defined property rights, the free market will generally allocate resources to their most efficient use as long as transaction costs are low. He developed an economic theory to indicate that broadcast licenses in a spectrum that was limited had high economic value, which could and should be paid for on the open market. Increasingly, spectrum licenses are offered via spectrum auctions, however this fails to consider non-commercial educational users, who are shut out of the process unless steps to ensure their fair consideration are taken.
The process of obtaining a new broadcast license can be very difficult and quite long, sometimes lasting years. A broadcast engineer must first determine an available frequency, of which none may be available in a crowded media market such as most major metropolitan areas. If one is available, an engineering study must be done and submitted with the application to the broadcasting authority, to prove that it will not cause RF interference with other stations. There was also a limited term for the license once it was acquired. According to the United State Government Printing Office in 1997, the term could exceed 8 years. This has been changed to 5 years and can be shorter depending on whether the FCC decides further evaluation 
There is often a two-step process by where a construction permit is first issued, with the license only being approved when the station certifies that the permit has been executed faithfully, after testing to ensure that all parameters are within allowable tolerances. Once a facility is built and operational, it may be allowed to operate under program test authority until the license is issued (or rarely, denied).
Where a station is close to an international border, a license may also need to be approved by the foreign country's broadcasting authority in addition to the domestic, as a form of mutual frequency coordination. This is done even if the border is outside of a station's predicted broadcast range, as unusual radio propagation due to weather often causes stations to reach well outside of their expected service area.
Existing stations also apply for permits and licenses when making changes to their facilities, such as relocation to another site, changing the radio antenna height, making changes to a directional antenna's radiation pattern, or when adding or converting to digital broadcasting. Other situations such as a change in the city of license are covered in rulemaking proceedings in the U.S., which may be a prerequisite to moving a station a significant distance, which would leave its original community outside of its new coverage area.
Temporary situations are covered by special temporary authority (STA) to operate at variance from the license or permit, or a restricted service license (RSL) to operate for a fixed period at low power. While these are U.S. FCC and U.K. Ofcom terms respectively, many other countries have similar permissions.
In the U.S., legal battles can drag the process out when mutually exclusive applications are received. This especially happens because the FCC opens application window periods of about a week, after available frequencies have been forced to sit idle for years. Some applications have been pending for years, while others end up in the administrative law courts or in arbitration, sometimes with one applicant seeking a buyout of another.
The broadcast license typically specifies the following information at minimum:
- geographic coordinates, with exact latitude and longitude
- carrier frequency and bandwidth
- modulation type[s]
- effective radiated power (ERP)
- height above average terrain (HAAT)
- directional antenna radiation pattern, specified at several azimuths
Additionally, they often specify the following:
- operating hours for mediumwave and shortwave
- transmitter power output (TPO), before any attenuation or gain
- broadcast auxiliary services (BAS), which link the studio and transmitter sites
- radio antenna brand and model
- height above mean sea level (AMSL) and above ground level (AGL)
backup facilities, which often have their own separate licenses
- additional service authorizations (subcarriers, digital radio)
Some countries also specify radio format or genre of television programming, in order to ensure diversity. This is the case with the Canadian Radio-television and Telecommunications Commission in Canada.
For community stations, such as class A television service and LPFM stations in the U.S., the license may require a certain amount of local content to be broadcast each week. In the case of U.S. broadcast translators, the license instead actually prohibits local community-serving content on FM, while LPTV stations may operate either way.
In rare cases, two stations may share time on the same frequency in the same area. In the city of New York, 89.1 has the unusual stipulation that the frequency is reserved for the United Nations, however the "vacant" allotment (the only one in the reserved band) is used by WNYU-FM and WNYU-FM1.
The form necessary for renewal of a broadcast license in the United States is the FCC Form 303-S. While the FCC Form 303-S License Application consists of yes/no questions and certifications, it process of renewing the license is not to be taken lightly. The FCC also requires that the licensees certify that they were in compliance with all rules and regulations during prior license term. If a licensee has been acquired in the middle of a term, they will be evaluated from that point on until the end of the license. It is extremely important to be as accurate as possible while answering any questions, because misrepresentation to the FCC could lead to loss of license.