Initiative won the business after a competitive pitch and will take over the account from 1 January 2018.
Carlsberg began the review earlier this year for its entire global media planning and buying business, which in addition to the Carlsberg brand includes Somersby cider and Tuborg beer. Ebiquity assisted the competitive pitch process.
The company last reviewed its global media account in 2013, when the business was worth £100m.
The account win for Initiative comes a year after it appointed Mat Baxter as global chief executive, replacing Jim Elms.
Fold7 handles Carlsberg’s creative account in the UK.
A spokeswoman for Carlsberg said: "Initiative was selected based on their excellent planning and buying expertise, unique proprietary tools, digital capabilities, transparency and the quality of their teams.
"We would also like to extend our thanks to our incumbent agency, OMD, who have been a great partner over the years, and also to all the agencies who have put in the time and effort to participate in our pitch."