Courtney Buses is one of only five operators selected from more than 230 entries for the accolade, which will be presented at the Hilton Hotel in London on Tuesday, November 19.
A recent independent survey showed that 95 per cent of Courtney passengers on its routes in Maidenhead, Bracknell and Windsor were happy with the service they received - 11 per cent more than the national average.
The Finchampstead based company has a fleet of 35 buses and, in 2002, became the first bus company in the UK to run its fleet on biofuel - which cut its carbon footprint by 97 per cent.
It is the second year in a row Courtney Buses has been short-listed.
Office manager Mandy Coles said: "This is really exciting news for us. Just to be nominated is an honour but to be short-listed a great achievement.
"We always strive to provide a first class service for our customers in Maidenhead and Windsor and this shows that we are succeeding."
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The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.