"This is truly a historic moment. For Finland, for Sweden, for NATO, and for our shared security," said NATO Secretary General Jens Stoltenberg.
Russia has repeatedly warned against this move. In response to the news regarding the potential NATO membership of Finland, Moscow had said a few weeks ago that it may have to take "military-technical" steps in response to Helsinki's moves.
Both Sweden and Finland had been non-aligned, that is, militarily neutral, for a long period of time.
The Russian invasion of Ukraine, however, pushed Finland and Sweden to seek membership of the intergovernmental military alliance.
The logic behind the move is simple. Joining NATO would allow Sweden and Finland to avoid a Ukraine-like scenario, where if attacked by an aggressor like Russia, other member States would be obligated to intervene against that aggressor in defence of the victim state.
This is the privilege that Ukraine had wanted for so long but did not attain.
All of NATO's 30 member countries hold the power to veto a new member.
Turkey was initially proving to be an obstruction to the entry of Finland and Sweden into NATO. But all three countries recently signed a "trilateral memorandum" to "extend their full support against threats to each other's security."