The United Nations' (UN) International Day of Nowruz celebrates the start of the Persian spring festival March 21 ever year. It occurs on or around the time of the March equinox.

World Down Syndrome Day  is observed on March 21. On this day, people with Down syndrome and those who live and work with them throughout the world organize and participate in activities and events to raise public awareness and create a single global voice for advocating for the rights, inclusion and well being of people with Down syndrome.

The International Day for the Elimination of Racial Discrimination is observed annually on 21 March. On that day, in 1960, police opened fire and killed 69 people at a peaceful demonstration in Sharpeville, South Africa, against the apartheid pass laws.

World Water Day is an annual event celebrated on 22 March. The day focuses attention on the importance of universal access to clean water, sanitation and hygiene (WASH) facilities in developing countries. The day also focuses on advocating for the sustainable management of freshwater resources.

World Tuberculosis Day, observed on March 24 each year, is designed to build public awareness about the global epidemic of tuberculosis (TB) and efforts to eliminate the disease. In 2012, 8.6 million people fell ill with TB, and 1.3 million died from the disease, mostly in the Third World.

International Day of Remembrance of the Victims of Slavery and the Transatlantic Slave Trade is a United nations international observance designated in 2007 to be marked on 25 March every year. The day honours and remembers those who suffered and died as a consequence of the transatlantic slave trade, which has been called "the worst violation of human rights […]

World Autism Awareness Day is an internationally recognised day on 2 April every year, encouraging Member States of the United Nationsto take measures to raise awareness about people with autism throughout the world.

6 April  declared as the International Day of Sport for Development and Peace (IDSDP) by the UN General Assembly. The adoption of this Day signifies the increasing recognition by the United Nations of the positive influence that sport can have on the advancement of human rights, and social and economic development.

The World Health Day is a global health awareness day celebrated every year on April 7, under the sponsorship of the World Health Organization (WHO), as well as other related organisations.