The Turkish parliament approved Finland's Nato membership application shortly before midnight Friday.
All MPs from President Recep Tayyip Erdogan's Justice and Development Party (AKP) and its nationalist ally the MHP were expected to vote in favour, along with most opposition MPs.
The tally was 276-0, or unanimous approval of all lawmakers present in the 600-seat legislature.
Under Turkish law, Erdogan must sign the bill within 14 days. Finland's application then goes to Washington for the final signatures.
The long-delayed vote ends a process that has dragged on for more than 10 months, with nearly all 30 Nato allies giving the green light to Finnish and Swedish membership by the end of last summer. Unanimous approval by current allies is required for any new members to join.
Only Turkey and Hungary have been holdouts, citing a variety of unresolved issues with the two Nordic countries – issues that are still keeping Sweden's membership bid in limbo.
After decades of staunchly maintaining its non-aligned status, Finland joined Nato's Partnership for Peace in 1994, and its Enhanced Opportunities Programme in 2004.
This year it is to finally become a full member of the trans-Atlantic alliance, leaving neighbouring Sweden as the only Nordic country that is outside the pact. The others – Denmark, Iceland and Norway – joined the alliance when it was founded in 1949. Finland's southern neighbour, Estonia, has been a Nato member since 2004.
After decades of general opposition to full Nato membership among the public in Finland and Sweden, there was a rapid, dramatic shift after the Russian invasion of Ukraine in February 2022.
The two nations submitted their applications together last May, under the general assumption that they would both be ratified relatively quickly.
Finland and Sweden did complete accession talks rapidly, with their Accession Protocols signed in early July. Since then, they have attended Nato meetings as official Invitees.
According to the Nato website, "once Allies have ratified the Accession Protocols according to their national procedures, Finland and Sweden will be invited to accede to the Washington Treaty, officially becoming Nato Allies".
Nato officials and politicians have continued to express hope that both countries will join the 30-member alliance before its summit in Vilnius, Lithuania, in mid-July.
Edited at 8:54 on 31 March for clarity.