Nokia Chief Executive Rajeev Suri will step down in September and is to be replaced by Pekka Lundmark, until now the CEO of energy group Fortum, the telecoms equipment maker said on Monday.
Suri steps down after more than a decade in charge of Nokia and Nokia Siemens Networks, the company said.
Nokia faces intense competition from Sweden's Ericsson and China's Huawei in the race to deliver 5G telecoms networks to operators around the world.
Lundmark, head of Fortum since 2015, held multiple executive positions at Nokia between 1990 and 2000, including vice president of strategy and business development at Nokia Networks.
"With the acquisition of Alcatel-Lucent behind us and the world of 5G in front of us, I am pleased that Pekka has agreed to join Nokia," Nokia Chairman Risto Siilasmaa said in a statement.