Almost 300 extra buses will be produced by Wrightbus over the next year in a major new contract with a Scottish transport company.
The Ballymena manufacturer will supply the vehicles to FirstGroup, the UK's largest provider of public transport, which has operations in Glasgow, Manchester and London as well as many other British cities and North America.
The deal is worth a potential £50 million over the next year.
Wright Group managing director Mark Nodder said: "This order shows FirstGroup's commitment to encouraging the public to make more use of public transport, which will reduce congestion and contribute to a cleaner environment.
"We are very pleased to feature so prominently in First's vehicle investment plans. We have continued to work very closely with First to develop a very strong product and after-sales support, which is reflected in the share of the business that we have won. Importantly too, it is also more good news for our workforce in Ballymena."
Wrightbus will begin work immediately on the contract, which is expected to generate between 280 and 290 buses. It will secure 1,000 jobs with the Co Antrim company.
Giles Fearnley, managing director of First UK Bus, said: "Our bus order is good news for customers, good news for British industry and in particular the transport sector. This demonstrates our confidence in the marketplace and reinforces our commitment to provide high quality services to our customers."
Leeds will receive its first Wrightbus hybrid double deckers. The vehicles use diesel and electric to minimise pollution.
Last month Wrightbus announced a major new order from the UK for 334 new buses.
The contract with bus operator Arriva is valued at around £55 million and consists of 204 double-deck and 130 single-deck buses.