The research company started in Belgium but more than 75% of its revenue is generated outside the country, and the new offices will service international companies based in London and Geneva.
Tim Duhamel, CEO of InSites Consulting, said: "The opening of these two new offices is the logical result of our growth objectives.
"A local team of consultants will be developed who look after the client contacts and manage projects with the support of the team in Ghent.
"Our centralised approach is the ideal foundation to work for international companies and headquarters."
Clients of the agency include Heinz, Heineken and RTL Nederland.
Christophe Vergult will be responsible for developing the London office while Niels Schillewaert takes the same role at Geneva. The new offices open on July 1.