GoCar currently operates in Dublin and Cork and the expanded agreement with Ford means that 70% of the rental fleet is now Ford cars and vans.
Often described as the 'car version of Dublin Bikes', the innovative rental service allows people to pick up a car when they need it - then drop it off where it suits.
A key advantage of the GoCar service is that the cars can be parked for free at on-street parking spaces Dublin.
The partnership will see Ford continue to supply the majority of GoCar vehicles, with the current fleet including some of Ireland's best-selling cars such as the Fiesta (GoCity Car) and Focus (GoTripper Car), plus Ford's practical light commercial vehicle, the Transit Connect (GoVan) - International Van of the Year 2014.
"Ford vehicles account for almost three-quarters of the GoCar fleet already, so it was an easy decision to build on our existing partnership," said Ford Ireland chief Eddie Murphy.
"GoCar is a great idea and a really nifty service for people who might need the use of a car or van once in a while, or for a short period of time.
"For Dublin customers, with city-centre parking costs continually rising, the option of parking for free at on-street parking spaces is a huge bonus."