The adoption of the Treaty on the Prohibition of Nuclear Weapons (TPNW) in New York, on July 7, 2017, shifted the paradigm in nuclear disarmament after more than twenty years of stagnation in the field. After biological and chemical weapons bans in 1972 and 1993, respectively, the remaining weapons of mass destruction will be banned once the TPNW enters into force. Even though there is considerable disagreement on the practical impact of a treaty for nuclear disarmament and international security, the award of the Nobel Peace Prize in 2017 to the International Campaign to Abolish Nuclear Weapons (ICAN), the coalition that was instrumental in the negotiations and adoption of the treaty, demonstrates the treaty’s significance and immediate impact.