The expansion marks the company's first international location outside of North America.
Based in Lisbon, BJSS' new team will support it existing international and regional Iberian clients, with up to 150 IT consultants set to be recruited.
Stuart Bullock, managing director at BJSS, said: "International expansion continues to be a key growth strategy for BJSS and we believe that the potential to unlock further opportunity in the European market is huge. The decision to expand to Lisbon as our first European base was a logical step in this strategy. It means that we can establish even closer ties with our European clients, while strengthening our service capabilities in the fast-growing Iberian markets. We're truly thrilled to be here."
Established in 1993 in Leeds, BJSS now employs more than 1,500 staff.