This is a calendar of events and festivals in the month of May.
- May 1: May Day or Labor Day, worldwide
- May 3: Constitution Memorial Day (憲法記念日 Kenpo kinenbi), Japan
- May 4: Bank Holiday (国民の休日), Japan
- May 5: Coronation Day is a public holiday in Thailand
- May 5: Children's Day (子供の日 Kodomo no hi), also known as Boys' Day (端午の節句 Tango no Sekku), Japan
- Until May 5: Golden Week in Japan, an extremely popular time to travel — best avoided as transport and accommodations are often booked solid
- May 6: international blood donation and free eye check up day worldwide