Orlistat is a product for obesity management approved by the US Food and Drug Administration.
Earlier this month, GSK received FDA approval to market OTC olistat in the USA under the brand name Alli and expects to launch it during the summer.
The financial terms of the agreement remains undisclosed.
As part of the licensing agreement, Roche will receive an upfront payment from GSK, which will be offset by a payment made by Roche to GSK as a part of a settlement agreement between the two companies relating to the licensing and co-marketing of carvedilol used in the treatment of mild to moderate congestive heart failure.
"Today's agreement strengthens GSK's innovative consumer healthcare portfolio, and gives us the opportunity to globalise our efforts around OTC orlistat," said John Clarke, president at GSK consumer healthcare.
"This exclusive license is also testament to GSK's ability to successfully switch prescription medicines to over the counter status and collaborate well with our partners.
Alongside our smoking control franchise, we now have brands dedicated to addressing two of the world's major health issues: smoking and obesity."
In 2005 OTC medicines generated sales of around £1.4m (€1.83) for the company, almost 50 per cent of the total sales from the firm's consumer healthcare division.
The company's other OTC products include analgesics, a range of smoking control products, gastro-intestinal and dermatological products.
Orlistat works by blocking enzymes digesting fat in the gut.
The OTC drug blocks nearly a third of the fat that is eaten.
The undigested fat is not absorbed into the body, it is passed out with the faeces.
Recently, GSK has announced a record-breaking licensing deal with biotech firm Genmab for their monoclonal antibody leukaemia treatment.
The deal was worth $2.1bn (€1.6bn), winning the title as the world's biggest licensing agreement and reaffirming GSK's position as the world's third largest pharmaceutical firm.