May

The International Day of Families is observed on the 15th of May every year. The Day was proclaimed by the UN General Assembly in 1993 with resolution A/RES/47/237 and reflects the importance the international community attaches to families. The International Day provides an opportunity to promote awareness of issues relating to families and to increase knowledge of the social, economic and demographic processes affecting families.

World No Tobacco Day (WNTD) is observed around the world every year on May 31. It is intended to encourage a 24-hour period of abstinence from all forms of tobacco consumption around the globe. The day is further intended to draw attention to the widespread prevalence of tobacco use and to negative health effects, which currently lead to nearly 6 million deaths each year worldwide, including 600,000 of which are the result of non-smokers being exposed to second-hand smoke. The member states of the World Health Organization (WHO) created World No Tobacco Day in 1987. In the past twenty-nine years, the day has been met with both enthusiasm and resistance around the globe from governments, public health organizations, smokers, growers, and the tobacco industry.

World Chronic Fatigue Syndrome Awareness Day celebrated on May 12.

National Technology Day of India celebrated on May 11.

International Nurses Day (IND) is an international day celebrated around the world on 12 May (the anniversary of Florence Nightingale's birth) of each year, to mark the contributions nurses make to society.

World Telecommunication and Information Society Day and ,Information Society Day celebrated on May 17.

World Red Cross and Red Crescent Day is an annual celebration of the principles of the International Red Cross and Red Crescent Movement. World Red Cross Red Crescent Day is celebrated on 8 May each year. This date is the anniversary of the birth of Henry Dunant (born 8 May 1828), the founder of International Committee of the Red Cross (ICRC) and the recipient of the first Nobel Peace Prize.

World Thyroid Day celebrated on May 25.

The purpose of World Turtle Day, May 23, sponsored yearly since 2000 by American Tortoise Rescue, is to bring attention to, and increase knowledge of and respect for, turtles and tortoises, and encourage human action to help them survive and thrive.

World Turtle Day is celebrated around the globe in a variety of ways, from dressing up as turtles or wearing green summer dresses, to saving turtles caught on highways, to research activities. Turtle Day lesson plans and craft projects encourage teaching about turtles in classrooms.

The "International Day of United Nations Peacekeepers", May 29, is "a day to pay tribute to all the men and women who have served and continue to serve in United Nations peacekeeping operations for their high level of professionalism, dedication, and courage and to honor the memory of those who have lost their lives in the cause of peace."

World Day for Cultural Diversity for Dialogue and Development, Anti-Terrorism Day of India celebrated on May 21.

World Metrology Day celebrates the signature by representatives of seventeen nations of the Metre Convention on 20 May 1875. The Convention set the framework for global collaboration in the science of measurement and in its industrial, commercial and societal application. The original aim of the Metre Convention – the worldwide uniformity of measurement - remains as important today as it was in 1875.

International Museum Day (IMD) is an international day a celebration that held every year on or around 18 May, coordinated by the International Council of Museums (ICOM). The event highlights a specific theme that changes every year and that is at the heart of the international museum community’s preoccupations.

World Hypertension Day(WHD) is a day designated and initiated by The World Hypertension League (WHL), which is itself an umbrella to organizations of 85 national hypertension societies and leagues. The day was initiated to increase the awareness of hypertension. This was especially important because of the lack of appropriate knowledge among hypertensive patients. The WHL launched its first WHD on May 14, 2005. Since 2006, the WHL has been dedicating May 17 of every year as WHD.

The International Day for Biological Diversity (or World Biodiversity Day) is a United Nations–sanctioned international day for the promotion of biodiversity issues. It is currently held on May 22.

The United Nations General Assembly declared May 3 to be World Press Freedom Day or just World Press Day to raise awareness of the importance of freedom of the press and remind governments of their duty to respect and uphold the right to freedom of expression enshrined under Article 19 of the 1948 Universal Declaration of Human Rights and marking the anniversary of the Windhoek Declaration, a statement of free press principles put together by African newspaper journalists in Windhoek in 1991.

28th May celebrated as International Day of Action for Women’s Health.

International Workers' Day, also known as Labour Day in some countries, and often referred to as May Day, is a celebration of labourers and the working classes that is promoted by the international labour movement which occurs every year on May Day (1 May), an ancient European spring festival.

1st Tuesday of May celebrated as World Asthma Day.

2nd Weekend of May celebrated as World Migratory Bird Day.