The United Nations General Assembly designates a number of "International Days" to mark important aspects of human life and history (the comprehensive list of all days celebrated by the United Nations and its Specialized Agencies is available here: International Days).

United Nations Specialized Agencies, including UNESCO, can also proclaim World Days. In this case, the proclamation of international days depends on their governing bodies and internal regulations only.

UNESCO thus celebrates UN International Days related to its fields of competence, in addition to the other World Days, proclaimed by the Organization's governing bodies or other institutions.

The list of official messages by the Director-General of UNESCO on the occasion of International Days with which UNESCO is associated is available here.

International Days observed at UNESCO

16 May 2016 International Day of Light
27 January 2018 International Holocaust Remembrance Day
11 February 2018 International Day of Women and Girls in Science
13 February 2018 World Radio Day
21 February 2018 International Mother Language Day
08 March 2018 International Women's Day
20 March 2018 International Francophonie Day
21 March 2018 International Day of Nowruz
21 March 2018 International Day for the Elimination of Racial Discrimination
21 March 2018 World Poetry Day
22 March 2018 World Water Day
06 April 2018 International Day of Sport for Development and Peace
23 April 2018 World Book and Copyright Day
30 April 2018 International Jazz Day
03 May 2018 World Press Freedom Day
05 May 2018 African World Heritage Day
21 May 2018 World Day for Cultural Diversity for Dialogue and Development
22 May 2018 International Day for Biological Diversity
05 June 2018 World Environment Day
08 June 2018 World Oceans Day
17 June 2018 World Day to Combat Desertification and Drought
18 July 2018 Nelson Mandela International Day
26 July 2018 International Day for the Conservation of the Mangrove Ecosystem
09 August 2018 International Day of the World's indigenous peoples
12 August 2018 International Youth Day
23 August 2018 International Day for the Remembrance of the Slave Trade and its Abolition
08 September 2018 International Literacy Day
15 September 2018 International Day of Democracy
20 September 2018 International Day of University Sport
21 September 2018 International Day of Peace
28 September 2018 International Day for Universal Access to Information
05 October 2018 World Teachers' Day
11 October 2018 International Day of the Girl Child
13 October 2018 International Day for Disaster Reduction
17 October 2018 International Day for the Eradication of Poverty
24 October 2018 United Nations Day
27 October 2018 World Day for Audiovisual Heritage
02 November 2018 International Day to End Impunity for Crimes against Journalists
05 November 2018 World Day of Romani Language
05 November 2018 World Tsunami Awareness Day
10 November 2018 World Science Day for Peace and Development
15 November 2018 World Philosophy Day
16 November 2018 International Day for Tolerance
25 November 2018 International Day for the Elimination of Violence against Women
29 November 2018 International Day of Solidarity with the Palestinian People
01 December 2018 World AIDS Day
03 December 2018 International Day of Persons with Disabilities
10 December 2018 Human Rights Day
18 December 2018 World Arabic Language Day
18 December 2018 International Migrants Day