As stated on the official website of the United Nations Office for Outer Space Affairs (UNOOSA):

The United Nations Office for Outer Space Affairs (UNOOSA) works to promote international cooperation in the peaceful use and exploration of space, and in the utilisation of space science and technology for sustainable economic and social development. The Office assists any United Nations Member States to establish legal and regulatory frameworks to govern space activities and strengthens the capacity of developing countries to use space science technology and applications for development by helping to integrate space capabilities into national development programmes.

Included in this endeavor, the UNOOSA provides an index of Space Agencies worldwide. The index includes the name, website URL, and contact information.

Visit the Worldwide Space Agencies Index at UNOOSA.