A new deal with Wales was sealed in late 2012 for last season, but the extension to that £1.5m per year agreement was dependent on the success of the November 2013 event.
Welsh economy minister Edwina Hart said Rally GB's interim results were strong enough for her to sign off budget for 2014 and '15.
"Wales Rally GB is one of our flagship events which gets worldwide coverage so I am particularly pleased that efforts to revitalise the event and attract more spectators and entries are paying off," she said.
AUTOSPORT's verdict on Rally GB's turnaround
Moving the event out of the south of Wales and basing it in Deeside instead of Cardiff was key to the rally's upturn.
"The people of North and Mid Wales are incredibly supportive of the event and local authorities and businesses have all reported increased economic activity in the area due to the rally," Hart added.
Rally GB chief executive Andrew Coe said: "We are, of course, absolutely delighted for the ongoing commitment from the Welsh Government.
"We are already making exciting plans to build on that success with an even bigger and better Wales Rally GB in November.
"What's more we now also have the fillip of a top Welsh driver, Elfyn Evans, competing in a front-running world championship team and that's another major boost both for Wales Rally GB and the sporting scene in Wales."