A primate city is a major city that works as the financial, political, and population center of a country and is not rivaled in any of these aspects by any other city in that country. Normally, a primate city must be at least twice as populous as the second largest city in the country. The presence of a primate city in a country usually indicates an imbalance in development — usually a progressive core, and a lagging periphery, on which the primate city depends for labor and other resources. Not all countries have primate cities (Germany, India, and the People's Republic of China for example), but in those that do, the rest of the country depends on it for cultural, economic, political, and major transportation needs. Among the best known examples of primate cities are alpha world cities of London and Paris. Other major primate cities include Athens, Baghdad, Bangkok, Buenos Aires, Cairo, Lima, Mexico City, Seoul, Tehran, and Vienna.

Some examples of nations without a primate city would include India, with the four main cities of Delhi, Mumbai, Kolkata and Chennai; Brazil, whose capital and political centre, Brasilia, is dwarfed in size and culture by São Paulo, Rio de Janeiro and Belo Horizonte; Italy, whose political seat at Rome is balanced by its business, financial and fashion "capital" of Milan; Australia, which has many large cities including Sydney, Melbourne and Brisbane, while the political centre resides in the smaller city of Canberra; South Africa, with three official capitals in Pretoria, Cape Town and Bloemfontein, each housing a different branch of government, and two cities larger than any of the above, namely the main commercial centre Johannesburg and largest port Durban; and the United States, whose financial and cultural centres are widely dispersed throughout the country in cities such as New York, Chicago, and Los Angeles and whose political centre is located in Washington, D.C. Germany's is unique, in that the Berlin political centre is somewhat weak. Several major government institutions are spread throughout the country, in cities like Bonn (the former capital) and Karlsruhe (seat of the federal constitutional court). Likewise, Frankfurt is its most important financial centre, but has significant competition from Düsseldorf and Munich. Germany's cultural center is split between Berlin, Munich, Cologne, Dresden, and smaller cities. Additionally, Mumbai, São Paulo, Sydney, and Berlin have close competitors as their countries' largest cities (Delhi, Rio de Janeiro, Melbourne, and Hamburg respectively).

Some countries, such as the United States, Australia and Canada, have regional and/or provincial/state primate cities, such as Atlanta, Georgia; Winnipeg, Manitoba; and Perth in Western Australia.