Which country was the latest to join NATO as of April 2023?

Finland was the latest country to join NATO as of April 2023. Its accession to NATO was a significant development in the context of European security, particularly in response to geopolitical tensions in the region. Finland officially became a NATO member on April 4, 2023, after decades of military non-alignment. The decision to join NATO was influenced by security concerns, especially following Russia's actions in Ukraine, prompting Finland to seek the collective defense assurances provided by NATO's Article 5.

Both Sweden and Ukraine are related to the topic because they have expressed interest in NATO membership, but as of April 2023, they had not completed the accession process like Finland. Estonia is already a member of NATO, having joined in 2004, so it does not fit the criteria of being the latest member.