The new company, which will be operational from 12 September, will be named DNV GL Group and headed up by current DNV CEO Henrik O Madsen. DNV will hold 63.5% of the new company with GL owner Mayfair holding 36.5%.
The last hurdle was cleared when the competition authorities in South Korea, US, EU and China gave the merger the go ahead.
The new company will provide certification and consultation services to the onshore and offshore wind industries. Testing, inspection and certification will be based in Arnhem, Netherlands, renewables consultancy will be situated in Bristol, England, while the offshore project certification business will be headquartered in Hamburg, Germany.
It will employ 17,000 people across 300 sites in more than 100 countries. In 2012 the companies had combined revenues of EUR 2.5 billion.
"DNV GL will be uniquely positioned to offer a broader set of products and services, more in-depth expertise and a denser global network of sites second to none," said Madsen.
"And importantly, there is a strong commitment by both DNV and GL to the merged company continuing to invest heavily in technology, research and innovation," he added.
The new business will be recognised as a Norwegian company.