Technical Associates was selected following a competitive pitch handled by The Duke of Edinburgh's Award International Association.
The agency has been retained for an initial six-month campaign, with half of its work being done on a pro-bono basis.
Technical Associates director Ian Clay said: 'It identified the need to get more organised on its approach to international PR.
'We'll be looking at promoting the awards by showing the benefits to businesses. In some countries such as Kenya and India, the awards can take children out of some difficult situations.'
The agency will start by building up a network of international media contacts.
The international award is a self-development programme available to all 14- to- 25-year-olds across more than 125 countries.
It has one of the widest global reaches of any youth development organisation.