The account was previously held by Aiken PR.
Priscilla O’ Regan, head of comms, BT (NI and Republic of Ireland), said: "It is a very exciting time for the BT brand globally and locally, and to support the business we need an agency that embodies the right blend of astute business acumen and fresh creative thinking. The team at Smarts Communicate has a history of success in achieving results for clients and we look forward to working with it to further drive BT’s external communications strategy."
Leontia Fetherston, joint managing director of Smarts Communicate, added: "We look forward to working with BT’s communications team and developing creative campaigns that will help support the growth of BT’s business."
Smarts Communicate is based in Belfast and operates in the UK and Ireland. The agency recently won the retained account for Lidl in Northern Ireland, as the retailer plans to expand in the country.