Belgium
Belgium boycotted the negotiations on the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017 and has consistently voted against the annual UN General Assembly resolutions on the Treaty, including in 2025. It may sign and ratify or accede to the TPNW, but will have to ensure the removal of the US nuclear weapons that it hosts at Kleine Brogel Air Base and make other changes to its policies and practices to become compliant.
TPNW Status
| Key weapons of mass destruction treaties | ||
|---|---|---|
| NUCLEAR WEAPONS | ||
| Party to the TPNW | No | |
| Party to the NPT | Yes (Ratified 1975) | |
| Ratified the CTBT | Yes (Ratified 1999, Annex 2 state) | |
| Party to an NWFZ | No | |
| CSA with the IAEA | Yes (In force 1977) | |
| AP with the IAEA | Yes (In force 2004) | |
| BIOLOGICAL AND CHEMICAL WEAPONS | ||
| Party to the BWC | Yes (Ratified 1979) | |
| Party to the CWC | Yes (Ratified 1997) | |
| TPNW Art. 1(1) prohibitions: Compatibility in 2025 | ||
|---|---|---|
| (a) | Develop, produce, manufacture, acquire | Compatible |
| Possess or stockpile | Compatible | |
| Test | Compatible | |
| (b) | Transfer | Compatible |
| (c) | Receive transfer or control | Compatible |
| (d) | Use | Compatible |
| Threaten to use | Compatible | |
| (e) | Assist, encourage or induce | Non-compatible |
| (f) | Seek or receive assistance | Non-compatible |
| (g) | Allow stationing, installation, deployment | Non-compatible |
| TPNW voting and participation | |
|---|---|
| UNGA resolution on TPNW (latest vote) | Voted no (2025) |
| Participated in 3MSP (2025) | No |
| Participated in 2MSP (2023) | Yes (observer) |
| Participated in 1MSP (2022) | Yes (observer) |
| Average MSP delegation size (% women) | 2 (75%) |
| Adoption of TPNW (7 July 2017) | N/A |
| Participated in TPNW negotiations (2017) | No |
| Negotiation mandate (A/RES/71/258) | Voted no |
| Fissile material | |
|---|---|
| Nuclear facilities | Yes |
| Fissile material production | No |
| HEU stocks | 100-1000 kg |
| Plutonium stocks | <50 kg |
| SQP with the IAEA | No |
Latest developments
In October 2025, Belgium participated in NATO's nuclear strike exercise, known as ‘Steadfast Noon’. It maintains dual-capable aircraft that could be used to deliver US nuclear weapons.1
Having observed the First Meeting of States Parties (1MSP) to the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2022 and 2MSP in 2023, Belgium opted not to observe 3MSP in March 2025.
In the Conference on Disarmament in February 2025, the Deputy Prime Minister of Belgium, Maxime Prévot, said: ‘A world without nuclear weapons is not just a noble ideal; it is a basic requirement for the survival of humanity.’2
At the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Preparatory Committee meeting in April 2025, Belgium described nuclear disarmament as ‘an endeavour fraught with multiple obstacles’, including heightened geopolitical tensions, the modernization of nuclear arsenals, the erosion of international law, and the increasing use of disruptive technology.3
It emphasized the need to prevent the further use of nuclear weapons. ‘Deterrence is part of preventing nuclear use,’ it claimed. ‘Belgium therefore fully supports NATO’s stance on the need for nuclear deterrence as long as adversaries possess nuclear weapons, and certainly when they threaten to use them against us.’4
In 2020, four former prime ministers and foreign ministers of Belgium—Willy Claes, Erik Derycke, Yves Leterme, and Guy Verhofstadt—were among the signatories to an open letter calling on current leaders in nuclear umbrella States to ‘show courage and boldness’ and join the Treaty on the Prohibition of Nuclear Weapons (TPNW).5
Recommendations
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Belgium should renounce the possession and potential use of nuclear weapons on its behalf, end the hosting of foreign nuclear weapons on its territory, and ensure that nuclear weapons do not have a role in its defence posture.
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Belgium should comply with its existing obligation under Article VI of the NPT and pursue negotiations in good faith on nuclear disarmament.
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Belgium should urgently adhere to the TPNW. Until it is in a position to do so, it should welcome the TPNW as a valuable component in the global disarmament and non-proliferation architecture, work with the Treaty's states parties on practical steps towards disarmament, and attend the meetings of states parties as an observer.