Quality Bakers managing director Roger Gray said it took a year to seal the "significant" deal.
He believed having a bakery in the South Island helped the company win the contract, as it was able to supply fresh buns to restaurants as opposed to the frozen buns Burger King previously shipped from the North Island.
The Kaikorai Valley bakery is now the southernmost producer of the fast-food chain's buns, which are made with a special recipe to worldwide specifications.
Nine full-time jobs have been created to cope with the extra work, bringing the total employed at the bakery to 64, Mr Gray said.
"It's great to know, in what has been a tough economic climate, that Quality Bakers Dunedin has been able to increase production so significantly, and provide greater employment opportunities for Dunedin locals."
