Members:

• FAO: Food and Agriculture Organization
• IAEA: International Atomic Energy Agency
• ICAO: International Civil Aviation Organization
• ILO: International Labour Organization
• IMO: International Maritime Organization
• ITU: International Telecommunication Union
• UN Regional Economic Commissions 
• UNCTAD: United Nations Conference on Trade and Development
• UNDP: United Nations Development Programme
• UNEP: United Nations Environment Programme
• UNESCO: United Nations Educational, Scientific and Cultural Organization
• UNFPA: United Nations Population Fund
• UNHCHR: United Nations High Commissioner for Human Rights
• UNHCR: United Nations High Commissioner for Refugees
• UNIDO: United Nations Industrial Development Organization
• UNU: United Nations University
• UPU: Universal Postal Union
• WFP: World Food Programme
• WHO: World Health Organization
• WIPO: World Intellectual Property Organization
• WMO: World Meteorological Organization
• World Bank
• WTO: World Trade Organization

The Secretary-General of the International Telecommunication Union serves as Chairman of HLSOC.

Observers:

• OECD: Organization for Economic Co-operation and Development
• IADB: Inter-American Development Bank
• IOM: International Organization for Migration
• UNFIP: United Nations Fund for International Partnerships
• UNITAR: United Nations Institute for Training and Research
• UNV: United Nations Volunteers