Finland will become a Nato member state after Turkey's parliament voted unanimously to approve its application.
Ankara had obstructed Finland's attempt to join the Western defence alliance for several months, accusing the Nordic country of "housing Kurdish terrorist organizations".
For any expansion of Nato, all its member states have to vote unanimously for the new addition to the alliance.
In a statement after the vote, Finnish President Sauli Niinistö said he wanted to thank all 30 Nato member states who had ratified Finland's membership.
"I want to thank every one of them for their trust and support," he said. "Finland will be a strong and capable ally, committed to the security of the alliance.
"We look forward to welcoming Sweden to join us as soon as possible," President Niinistö added.
Sweden, which applied to join Nato last May, is still being blocked from joining by Turkey due to similar complaints as Finland faced, from President Recep Tayyip Erdogan.
Sweden and Finland previously followed a policy of neutrality and non-alignment with Nato.
This sentiment changed after the Russian invasion of Ukraine in February 2022.
Nato Secretary General Jens Stoltenberg congratulated Finish President Sauli Niinistö on Twitter, saying: "I look forward to raising Finland's flag at Nato HQ in the coming days.
"Together we are stronger & safer," he wrote.
Russia spans the whole of the Eurasian continent, sharing a border with North Korea and China to the east and Norway and Finland in the north.
The border between Russia and Finland is 1,340km (832 miles) and is the longest of any European Union member.
To secure the border, Finland began building a 200km (124 miles) fence separating itself from Russia in February.
At the time of the full-scale Russian invasion of Ukraine, analysts and experts drew parallels with the Soviet invasion of Finland in 1939.
Like Ukraine, Finland had to defend itself, against a much bigger neighbour.