21 February
International Mother Language Day
8 March
International Women's Day
24 March
World TB Day
7 April
World Health Day
23 April
World Book and Copyright Day
21 May
World Day for Cultural Diversity for Dialogue and Development
31 May
World No-Tobacco Day
1 June
International Children's Day
5 June
World Environment Day
20 June
World Refugee Day
26 June
International Day against Drug Abuse and Illicit Trafficking
11 July
World Population Day
16 September
International Day for the Preservation of the Ozone Layer
21 September
International Day of Peace
5 October
World Teacher's Day
9 October
World Post Day
14 October
International Day for Disaster Reduction
16 October
World Food Day
16-18 October
MDGs/Stand up against Poverty
17 October
International Day for the Eradication of Poverty
24 October
United Nations Day
16 November
International Day for Tolerance
25 November
Internatioanl Day for the Elimination of Violence against Women
1 December
World AIDS Day
5 December
International Volunteer Day for Economic and Social Development
10 December
Human Rights Day
For more detials see "United Nations Conferences and Observances [pdf]