The ruling, which allows both companies to use the famous trademark in Britain, is an important win for Budvar in its third largest export market.
It also highlights the risk of allowing the co-existence of the brands in other markets.
The Czech brewer, which sold 1.3 million hectolitres of beer worldwide in 2011, and its larger rival, which sold 399.4 million hectolitres, are still fighting 11 court cases in 8 different countries.
The UK ruling followed a decision by the European Court of Justice in 2011.
The UK Supreme Court's ruling was final, Budvar said.
AB InBev said it was disappointed by the UK Supreme Court ruling but that it did not affect its Budweiser trademark in the country. It said Budweiser sales in the UK rose 40 percent between 2009 and 2011.
"This attempt to change the final decision of the court proves the long-term strong interest by (AB InBev) to gain exclusive rights for the Budweiser brand at any cost," Budvar Chief Executive Jiri Bocek said in a statement.
Budvar's brewery is in the Czech town of Ceske Budejovice, known as Budweis in German, where brewing dates back to the 13th century.
When the Budvar brewery started in 1895, U.S. brewer Anheuser-Busch, now part of Anheuser-Busch InBev, had already been making Budweiser beer for 19 years.
Budvar entered the UK market in 1973 and Anheuser-Busch in 1974. The latter applied to have the word Budweiser registered as a trademark in 1979. While this was being examined, Budvar also submitted a trademark application for its Budweiser in 1989.
British courts ruled in 2000 that both companies could each register Budweiser, which duly entered the Trade Marks Register on May 19 of that year.
