Round 2 plans to open a London office for the agency and says it was attracted to Robson Brown because it has a strong regional and national profile.
The agency, which has handled advertising, creative, digital, PR, media planning and buying, print and design work for clients including Dreams, Flymo and Newcastle Building Society has an annual turnover of £37m.
Round 2 managing director Andrew Marwick has been appointed as chief executive of both Round 2 International-UK and Robson Brown.
Tom Hedley, Duncan McEwan and Susan Langston will join the UK board of Round 2 International as executive directors alongside their current roles of board directors of Robson Brown.
The agency, which has more than 90 staff, was launched in 1983 by Alan Brown and Stuart Robson.
Round 2 International-UK chairman Garfield Ricketts, says: “Robson Brown has a great deal of synergy with Round 2 International and has major strengths in terms of qualities, capabilities and strength of management which supports Round 2 International ’s European expansion plans.”