How Long Does It Take for a Country to Become a NATO Member?

When Finland and Sweden asked to join NATO earlier this year in defiance of the Kremlin's threat that such a decision would bring about "serious military and political consequences," the two countries were promised they will become part of the alliance "as quickly as possible."

But almost four months after NATO formally invited Finland and Sweden to join the alliance, as required by protocol, the two Scandinavian countries appear nowhere closer to calling themselves NATO members and concerns are growing in Europe over delays in ratifying their accession.

There's not a set amount of time it takes for countries to join NATO as the process is not formalized and phases can vary, so opinions are split over how long it would take for Finland and Sweden to enter the alliance.

For the most recent states to join NATO—Montenegro in 2017 and North Macedonia in 2020—the ratification process took about a year and a half and just about a year respectively.

Montenegro, which was formally invited on December 2, 2015, finally joined NATO on June 5, 2017. North Macedonia, whose accession to the alliance had been vetoed by Greece in 2008, was formally invited to join NATO on February 6, 2019, and officially accessed the alliance on March 27, 2020.

Other countries that previously joined NATO did so in an even longer time, including Romania and Bulgaria, for which the process took about two years.

"The application process is relatively straightforward. Any sovereign nation in the Euro-Atlantic area, broadly speaking, can apply," Kenton White, a lecturer in Strategic Studies and International Relations at the University of Reading, told Newsweek.

"They must have the capacity to meet the political, legal and military obligations NATO demands," he said. "A working democratic political system and the capacity to meet the military demands placed upon it are the main preconditions for membership. These preconditions are also the main delays in the accession process."

How Long Will It Take Sweden and Finland to Join NATO?

After Finland and Sweden had expressed their desire to join the alliance, NATO officials said this summer that Finland's application could be completed in less than the four months it took West Germany, Turkey and Greece to join in the 1950s, when there were only the original 12 member countries in the alliance.

NATO Secretary-General Jens Stoltenberg told Euronews that the process would be "the fastest" in the history of the alliance and will take months, rather than years.

"There is a strong political will to ratify in the different allied countries," Stoltenberg said.

Months after Stoltenberg made this prediction, his words sound like wishful thinking, though the secretary-general still believes Finland and Sweden's process of joining the alliance will be the fastest in NATO's modern history.

"Joining the Alliance will make you safer, NATO stronger and the Euro-Atlantic area more secure," Stoltenberg said during a meeting with Swedish Prime Minister Ulf Kristersson at NATO Headquarters on Thursday.

Stoltenberg said that nearly all NATO allies have completed their national procedures. To ratify the two countries' access to the alliance, a final unanimous vote by all NATO members is required. At the moment, Turkey is holding up the process.

Istanbul previously threatened to veto Finland and Sweden's bid for membership over accusations that the countries acted as safe havens for terrorists, including members of the Kurdistan Workers' Party (the PKK), and is now waiting for Helsinki and Stockholm to give the security assurances requested.

All other members of NATO, besides Turkey and Hungary, have already ratified Finland and Sweden's membership.

"It is impossible to say how long it will take Finland and Sweden to join fully, but because of the existing cooperation between the European countries and NATO the likelihood of problems (outside Hungary's and Turkey's objections) will be minimal," White said.

"There hasn't been much progress with Turkey and Hungary. NATO is still awaiting their ratification of the applications. This is more to do with their internal politics than any clear problem with Sweden's or Finland's applications. Hungary has ties with Russia and this may also influence the time it takes for ratification."

Which Other Countries Want to Join NATO?

There are at least three other countries who have asked to join the alliance: Ukraine, Bosnia and Herzegovina, and Georgia.

Ukraine applied for NATO membership in September 2022, while Bosnia and Herzegovina and Georgia formally informed NATO of their wish to become members earlier in the year.

"Bosnia and Herzegovina, Georgia and Ukraine all aspire to membership," said White. "They are all at different stages of application or preparation. Clearly, Ukraine cannot become a member while it is engaged in a war with Russia."

Kosovo has also expressed its aspiration to eventually join the alliance, but the country is still far from being able to undertake the commitments and obligations required by the membership.