While NATO members agree Kyiv cannot join during the war, they have disagreed over how quickly it could happen afterwards and under what conditions.
Negotiations have also focused on what conditions Ukraine would have to meet to join NATO and how its progress should be tracked, diplomats say.
"I am absolutely certain that we will have unity and a strong message on Ukraine," Stoltenberg told reporters.
Russia's invasion of Ukraine in February last year prompted Nordic neighbours Finland and Sweden to abandon decades of military non-alignment and apply to join NATO.
Sweden, backed by Stoltenberg and many NATO members, said it had kept all its undertakings to Turkey on the issue.
Persons:
Volodymyr Zelenskiy, Zelenskiy, General Stoltenberg, Stoltenberg, Maria Zakharova, Tayyip Erdogan, Ulf Kristersson, Erdogan, Kristersson, Ronald Popeski, Lidia Kelly, Stephen Coates
Organizations:
NATO, Diplomats, Alliance, Twitter, Russian Foreign, Nordic, Kurdistan Workers Party, EU, European Union, Thomson
Locations:
VILNIUS, Vilnius, Sweden, Lithuanian, Ukraine, Moscow, Eastern Europe, Russia, United States, Germany, NATO, Finland, Turkey, Ankara, Swedish