The bakery chain has been trialling delivery of its products in London, Newcastle and Glasgow and will extend the service to Bristol and Birmingham this week.
It will roll out to Manchester, Leeds, Sheffield and Nottingham in the spring, with a plan to achieve national coverage by the end of the year.
Greggs, which has 2,050 UK stores, first became available on Just Eat in Newcastle last June.
In the last seven months the top selling delivery items have included the sausage roll, vegan sausage roll and steak bake.
Andrew Kenny, managing director at Just Eat UK, says the partnership has proved particularly popular for breakfast orders, which can be placed from 7am with no minimum spend.
Earlier this month Greggs announced it was to make a one-off £7m bonus payment to employees following an ‘exceptional year’ for the business.
In its fourth quarter trading update, the company reported like for like sales growth of 9.2%.
Total sales were up 13.5%, with a net 97 stores opening in 2019.