His departure comes after the three organisations that own the group - NFU Scotland, the Meat and Livestock Commission and the Scottish Association of Meat Wholesalers - decided not to reappoint Walker as the body’s chairman.
Walker has been chairman of Quality Meat Scotland since 2003. He was previously president and vice president of NFU Scotland for five years. He is also a farmer from south west Scotland and has interests in a number of other companies.
Quality Meat Scotland said that it would start the formal process that was required to appoint a new chairman as soon as possible.
Meanwhile, the group has appointed Donald Biggar as interim chairman. Biggar, who is also a farmer and a previous director of QMS, will take up his position with immediate effect.