Earth Day is a name used by two different observances held annually in the (northern) spring, both intended to inspire awareness of and appreciation for the Earth's environment. Earth Day is in the public domain and open to all persons to shape. Some grassroots Earth Day organizers seek to move the date of the observance to the Summer Solstice, to take advantage of the warm temperatures in the Northern Hemisphere (where most people live) to create greater participation.

Administrative Professionals' Day (previously known as Secretary's Day) is an unofficial secular holiday observed on the last Wednesday of April (April 26 in 2006 April 25 in 2007), to recognize the work of clerical employees such as administrative assistants, receptionists, paralegals, etc. It is celebrated as part of a larger Administrative Professionals Week, which takes place during the last full week of April.

Cinco de Mayo ("The Fifth of May" in Spanish) is a national holiday in Mexico which is also widely celebrated in the United States. It commemorates the victory of Mexican forces led by General Ignacio Zaragoza over the French occupational forces in the Battle of Puebla on 05 May 1862.

Mother's Day is a day honoring mothers, celebrated on various days in many places around the world. Mothers often receive gifts on this day.

The modern Mother's Day holiday was created by Anna Jarvis, as a day to honor mothers and motherhood; especially within the context of families, and family relationships. It is now celebrated on various days, in many parts of the world. Father's Day is a corresponding holiday honoring fathers.

In the United States, Armed Forces Day is celebrated on the third Saturday in May. The day was created in 1949, and was a result of the consolidation of the military services in the Department of Defense. It was intended to replace the separate Army, Navy, Air Force, Marine Corps, and Coast Guard Days, but observance of these days, especially within each particular service, continues to this day.