The former Greek foreign minister Theodoros Pangalos was among the signatories to an open letter in September 2020 calling on current leaders to “show courage and boldness – and join the treaty”.

Greece voted against a UN General Assembly resolution in 2019 that welcomed the adoption of the treaty and called upon “all states that have not yet done so to sign, ratify, accept, approve, or accede to the treaty at the earliest possible date”.

On the opening day of the TPNW negotiating conference in 2017, Greece joined the United States and several other states in protesting the treaty-making process.

In 2016, Greece voted against the UN General Assembly resolution that established the formal mandate for states to commence the negotiations in 2017 on “a legally binding instrument to prohibit nuclear weapons, leading towards their total elimination”.

In a “non-paper” sent to NATO members ahead of the vote, the United States “strongly encourage[d]” members, including Greece, to vote against the resolution, “not to merely abstain”. In addition, it said that, if the treaty negotiations do commence, allies and partners should "refrain from joining them”.