| Wed, May 1 | Batman Day | - | |
| Wed, May 1 | Labor Day / May Day | Multiple [Show] | Multiple Types |
| Wed, May 1 | Yom HaShoah | Multiple [Show] | Jewish Holiday |
| Wed, May 1 | Labor Day | Multiple [Show] | Multiple Types |
| Wed, May 1 | Agriculture and Labor Day | Haiti | National/legal Holiday |
| Wed, May 1 | National Workers Day | Saint vincent and the grenadines | Public Holiday |
| Wed, May 1 | Labour Day | Multiple [Show] | Multiple Types |
| Wed, May 1 | Unity Day | Kazakhstan | Public Holiday |
| Wed, May 1 | May Day | Multiple [Show] | Multiple Types |
| Wed, May 1 | Worker's Day | Multiple [Show] | Public Holiday |
| Wed, May 1 | Spring and Labor Day | Russia | National Holiday |
| Wed, May 1 | Yom HaShoah/Holocaust Memorial Day | Israel | Observance, Hebrew |
| Wed, May 1 | Labour Day/May Day | Multiple [Show] | Multiple Types |
| Wed, May 1 | International Workers' Day | Eritrea | Public Holiday |
| Wed, May 1 | International Labor Day | Multiple [Show] | Multiple Types |
| Wed, May 1 | International Day of Solidarity of Workers | Moldova | National Holiday |
| Wed, May 1 | Workers Day | Zimbabwe | Public Holiday |
| Wed, May 1 | Labor day | Multiple [Show] | Multiple Types |
| Wed, May 1 | Workers' Day | Multiple [Show] | Public Holiday |
 |
| Wed, May 1 | Prayer Day | Faroe islands | Public Holiday |
| Wed, May 1 | May 1st | Sweden | Public Holiday |
| Wed, May 1 | Labor holiday | Serbia | National Holiday |
| Wed, May 1 | Labor and Solidarity Day | Turkey | National Holiday |
| Wed, May 1 | International Labour Day | Kosovo | Official Holiday |
| Wed, May 1 | Feast of St Joseph the Worker | Holy see (vatican city) | National Holiday |
| Wed, May 1 | Law Day | United states | Observance |
| Wed, May 1 | Loyalty Day | United states | Observance |
| Wed, May 1 | Maharashtra Day | India | State Holiday |
| Thu, May 2 | Spring and Labor Day Holiday | Russia | National Holiday |
| Thu, May 2 | Labor Day (Day 2) | Bosnia and herzegovina | Public Holiday |
| Thu, May 2 | Labour Day/May Day (day 2) | Montenegro | National Holiday |
| Thu, May 2 | Labour Day holiday | Slovenia | National Holiday |
| Thu, May 2 | Day of Madrid | Spain (Madrid) | Local Holiday |
| Thu, May 2 | Labor holiday second day | Serbia | National Holiday |
| Thu, May 2 | Labor Day Holiday | Ukraine | National Holiday |
| Thu, May 2 | National Day of Prayer | United states | Observance |
| Fri, May 3 | World Press Freedom Day | - | International |
| Fri, May 3 | Spring and Labor Day Holiday | Russia | National Holiday |
| Fri, May 3 | Cross Day | El salvador | Observance |
| Fri, May 3 | Constitution Day | Poland | National Holiday |
| Fri, May 3 | Constitution Memorial Day | Japan | National Holiday |
| Fri, May 3 | No Pants Day | - | Weird |
| Sat, May 4 | Literary Day | Taiwan | Observance |
| Sat, May 4 | Youth Day | China | Observance |
| Sat, May 4 | Independence Restoration Day | Latvia | National Holiday |
| Sat, May 4 | Remembrance Day | Netherlands | Observance |
| Sat, May 4 | Greenery Day | Japan | National Holiday |
| Sat, May 4 | Cassinga Day | Namibia | Public Holiday |
| Sat, May 4 | Anniversary of the Decease of M. R. ŝtefánika | Slovakia | Observance |
| Sat, May 4 | Daylight Saving Time ends | Morocco | Clock Change/daylight Saving Time |
| Sat, May 4 | Kent State Shootings Remembrance | United states (Ohio) | Local Observance |
| Sat, May 4 | Rhode Island Independence Day | United states (Rhode Island) | Local Observance |
| Sat, May 4 | National Explosive Ordnance Disposal (EOD) Day | United states | Observance |
| Sat, May 4 | World Naked Gardening Day | - | Weird |
| Sun, May 5 | Arrival Day | Guyana | Public Holiday |
| Sun, May 5 | Europe Day | Germany | Observance |
| Sun, May 5 | Children's Day | Multiple [Show] | National Holiday |
| Sun, May 5 | Battle of Puebla | Mexico | Observance |
| Sun, May 5 | Mothers' Day | Multiple [Show] | Observance |
| Sun, May 5 | Senior Citizens Day | Palau | Public Holiday |
| Sun, May 5 | Freedom Day | Ethiopia | Public Holiday |
| Sun, May 5 | Liberation Day | Netherlands | Observance |
| Sun, May 5 | Mother's Day | Romania | Observance |
| Sun, May 5 | Constitution Day of the Kyrgyz Republic | Kyrgyzstan | Public Holiday |
| Sun, May 5 | Cinco de Mayo | United states | Observance |
| Mon, May 6 | National Nurses Day | United states | Observance |
| Mon, May 6 | Ramadan begins | Multiple [Show] | Multiple Types |
| Mon, May 6 | Labour Day | Multiple [Show] | Public Holiday |
| Mon, May 6 | Ramadan starts | Multiple [Show] | Multiple Types |
| Mon, May 6 | Martyr's Day | Lebanon | Observance |
| Mon, May 6 | Martyrs' Day | Syria | Public Holiday |
| Mon, May 6 | St. George's Day | Bulgaria | National Holiday |
| Mon, May 6 | Memorial Day/Parents' Day | Moldova | National Holiday |
| Mon, May 6 | Early May Bank Holiday | United kingdom | Bank Holiday |
| Mon, May 6 | May Day | Multiple [Show] | Multiple Types |
| Mon, May 6 | Children's Day observed | Japan | National Holiday |
| Mon, May 6 | Day of Gorans | Kosovo | Observance |
| Mon, May 6 | International No Diet Day | - | Weird |
| Tue, May 7 | Defender of the Fatherland Day | Kazakhstan | Public Holiday |
| Tue, May 7 | Soldiers' Day | El salvador | Observance |
| Tue, May 7 | Teacher's Day | United states | Observance |
| Wed, May 8 | Victory Day | Multiple [Show] | Public Holiday |
| Wed, May 8 | World Ovarian Cancer Day | - | International |
| Wed, May 8 | Time of Remembrance and Reconciliation for Those Who Lost Their Lives during the Second World War | - | International |
| Wed, May 8 | End of the Second World War | Multiple [Show] | Multiple Types |
| Wed, May 8 | Yom HaZikaron (Memorial Day) | Israel | Observance, Hebrew |
| Wed, May 8 | WWII Victory Day | Multiple [Show] | Multiple Types |
| Wed, May 8 | Parents' Day | South korea | Observance |
| Wed, May 8 | Victory in Europe Day | Czech republic | National Holiday |
| Wed, May 8 | Day of liberation | Norway | Observance, Flag Day |
| Wed, May 8 | Commemoration National Heroes WWII | Turkmenistan | Public Holiday |
| Wed, May 8 | Congress | Armenia | Observance |
| Wed, May 8 | End of World War II | Slovakia | National Holiday |
| Wed, May 8 | Truman Day | United states (Missouri) | State Holiday |
| Thu, May 9 | Yom HaAtzmaut | Multiple [Show] | Jewish Holiday |
| Thu, May 9 | Victory Day | Multiple [Show] | Multiple Types |
| Thu, May 9 | Remembrance Day | Uzbekistan | Public Holiday |
| Thu, May 9 | Yom HaAtzmaut (Independence Day) | Israel | National Holiday, Hebrew |
| Thu, May 9 | Liberation Day | Multiple [Show] | Multiple Types |
| |
| Thu, May 9 | Victory and Peace Day | Armenia | National Holiday |
| Thu, May 9 | Europe Day | Kosovo | Official Holiday |
| Thu, May 9 | Victory Day / Memorial Day | Ukraine | National Holiday |
| Thu, May 9 | Yom Ha'atzmaut | United states | Jewish Holiday |
| Fri, May 10 | Mothers' Day | El salvador | National Holiday |
| Fri, May 10 | Mother's Day | Mexico | Observance |
| Fri, May 10 | Constitution Day | Micronesia | Public Holiday |
| Fri, May 10 | State Holiday | United states (South Carolina) | Multiple Types |
| Sat, May 11 | World Migratory Bird Day | - | International |
| Sat, May 11 | Astronomy Day | - | Weird |
| Sun, May 12 | Mother's Day | Multiple [Show] | Multiple Types |
| Sun, May 12 | Mothers' Day | Multiple [Show] | Multiple Types |
| Sun, May 12 | Buddha's Birthday | Multiple [Show] | Multiple Types |
| Sun, May 12 | Mother´s Day | Cuba | Observance |
| Sun, May 12 | St Andrew's Day | Georgia | Public Holiday |
| Sun, May 12 | Day of the National Emblem and Flag of Belarus | Belarus | Observance |
| Sun, May 12 | Father's Day | Romania | Observance |
| Sun, May 12 | International Nurses Day | - | International |
| Mon, May 13 | Gospel Day | Tuvalu | Public Holiday |
| Tue, May 14 | National Holiday | Paraguay | National Holiday |
| Tue, May 14 | Kamuzu Day | Malawi | Public Holiday |
| Tue, May 14 | National Unification Day | Liberia | Public Holiday |
| Wed, May 15 | Independence Day | Paraguay | National Holiday |
| Wed, May 15 | International Day of Families | - | International |
| Wed, May 15 | Teacher´s Day | Colombia | Observance |
| Wed, May 15 | Europe Day | Moldova | Observance |
| Wed, May 15 | Family Day | Multiple [Show] | Observance |
| Wed, May 15 | Teacher's Day | Mexico | Observance |
| Wed, May 15 | Feast Day of St Isidore | Spain (Madrid) | Local Holiday |
| Wed, May 15 | Peace Officers Memorial Day | United states | Observance |
| Thu, May 16 | General Prayer Day | Greenland | Public Holiday |
| Thu, May 16 | SPLA Day | South sudan | Public Holiday |
| Fri, May 17 | Constitution Day | Nauru | Public Holiday |
| Fri, May 17 | World Information Society Day | - | International |
| Fri, May 17 | 17 May Constitution Day (1814) | Norway | National Holiday, Flag Day |
| Fri, May 17 | Galicia Literature Day | Spain (Galicia) | Local Holiday |
| Fri, May 17 | Liberation Day | Congo democratic republic | Public Holiday |
| Fri, May 17 | Great Prayer Day | Denmark | National Holiday |
| Fri, May 17 | National Defense Transportation Day | United states | Observance |
| Fri, May 17 | Bike to Work Day | - | Weird |
| Sat, May 18 | Flag Day/University Day | Haiti | National/legal Holiday |
| Sat, May 18 | International Museum Day | Singapore | Observance |
| Sat, May 18 | Battle of Las Piedras | Uruguay | Observance |
| Sat, May 18 | Day of Revival, Unity, and the Poetry of Magtymguly | Turkmenistan | Public Holiday |
| Sat, May 18 | Europe Day | Ukraine | Observance |
| Sat, May 18 | Armed Forces Day | United states | Observance |
| Sun, May 19 | Day of Vesak | - | International |
| Sun, May 19 | Commemoration of Atatürk, Youth and Sports Day | Turkey | National Holiday |
| Mon, May 20 | Victoria Day | Canada (All Except Ns , Nu , Qc) | Common Local Holidays |
| Mon, May 20 | National Patriots' Day | Canada (Quebec) | Local Holiday |
| Mon, May 20 | Restoration of Independence Day | East timor | Public Holiday |
| Mon, May 20 | World Autoimmune Arthritis Day | - | International |
| Mon, May 20 | Independence Day | Cuba | Observance |
| Mon, May 20 | National Day | Cameroon | Public Holiday |
| Mon, May 20 | Discovery Day | Cayman islands | Public Holiday |
| Tue, May 21 | Saint Helena's Day | Saint helena | Public Holiday |
| Tue, May 21 | Navy Day | Chile | National Holiday |
| Tue, May 21 | World Day for Cultural Diversity for Dialogue and Development | - | International |
| Tue, May 21 | Independence Day | Montenegro | National Holiday |
| Wed, May 22 | International Day for Biological Diversity | - | International |
| Wed, May 22 | Independence Day (day 2) | Montenegro | National Holiday |
| Wed, May 22 | Unity Day | Yemen | Public Holiday |
| Wed, May 22 | Emergency Medical Services for Children Day | United states | Observance |
| Wed, May 22 | National Maritime Day | United states | Observance |
| Wed, May 22 | Harvey Milk Day | United states (California) | Local Observance |
| Thu, May 23 | Lag B'Omer | Multiple [Show] | Multiple Types |
| Thu, May 23 | International Day to End Obstetric Fistula | - | International |
| Thu, May 23 | Constitution Day | Germany | Observance |
| Thu, May 23 | Labor Day / May Day | Jamaica | Public Holiday |
| Thu, May 23 | Vlach’s National Day (for Vlach community) | Macedonia, republic of | Optional Holiday |
| Thu, May 23 | Lag BaOmer | United states | Jewish Holiday |
| Thu, May 23 | World Turtle Day | - | Weird |
| Fri, May 24 | Commonwealth Day | Belize | Public Holiday |
| Fri, May 24 | The Battle of Pichincha | Ecuador | National Holiday |
| Fri, May 24 | Culture and Literacy Day | Bulgaria | National Holiday |
| Fri, May 24 | Independence Day | Eritrea | Public Holiday |
| Fri, May 24 | Bermuda Day | Bermuda | Public Holiday |
| Fri, May 24 | Saints Cyril and Methodius' Day | Macedonia, republic of | National Holiday |
| Sat, May 25 | Towel Day | - | Weird |
| Sat, May 25 | African Liberation Day | - | International |
| |
| Sat, May 25 | National Day/May 1810 Revolution | Argentina | National Holiday |
| Sat, May 25 | Liberation and Resistance Day | Lebanon | Observance |
| Sat, May 25 | Independence Day | Jordan | National Holiday |
| Sat, May 25 | Africa Day | Multiple [Show] | Public Holiday |
| Sat, May 25 | Africa Freedom Day | Zambia | Public Holiday |
| Sat, May 25 | African Union Day | Ghana | Public Holiday |
| Sat, May 25 | National Missing Children's Day | United states | Observance |
| Sat, May 25 | National Wine Day | - | Weird |
| Sun, May 26 | Mother's Day | Multiple [Show] | Multiple Types |
| Sun, May 26 | Independence Day | Multiple [Show] | Public Holiday |
| Sun, May 26 | Dniester Day | Moldova | Observance |
| Sun, May 26 | Martyrdom of Imam Ali | Iran | National Holiday |
| Sun, May 26 | Carpet Day | Turkmenistan | Observance |
| Sun, May 26 | National Sorry Day | Australia | Observance |
| Sun, May 26 | Cultural Workers and Folk Artists Day | Ukraine | Observance |
| Sun, May 26 | Kiev Day | Ukraine | Observance |
| Mon, May 27 | Memorial Day | Multiple [Show] | Multiple Types |
| Mon, May 27 | Mother Day | Bolivia | Observance |
| Mon, May 27 | Spring Bank Holiday | Multiple [Show] | Multiple Types |
| Mon, May 27 | Children's Day | Nigeria | Observance |
| Mon, May 27 | African Union Day observed | Ghana | Public Holiday |
| Mon, May 27 | Jefferson Davis Birthday | United states (Mississippi) | Local Observance |
| Tue, May 28 | Hamburger Day | - | Weird |
| Tue, May 28 | Republic Day | Armenia | National Holiday |
| Tue, May 28 | Derg Downfall Day | Ethiopia | Public Holiday |
| Wed, May 29 | International Day of United Nations Peacekeepers | - | International |
| Wed, May 29 | Democracy Day | Nigeria | Public Holiday |
| Thu, May 30 | Ascension Day | Multiple [Show] | Multiple Types |
| Thu, May 30 | Harvest Festival | Malaysia | Common Local Holidays |
| Thu, May 30 | Indian Arrival Day | Trinidad and tobago | Public Holiday |
| Thu, May 30 | Anguilla Day | Anguilla | Public Holiday |
| Thu, May 30 | Day of the Canary Islands | Spain (Canary Islands) | Local Holiday |
| Thu, May 30 | Mothers' Day | Nicaragua | Observance |
| Fri, May 31 | Laylat al-Qadr (Night of Destiny) | Multiple [Show] | Multiple Types |
| Fri, May 31 | Harvest Festival Day 2 | Malaysia | Common Local Holidays |
| Fri, May 31 | National Heroes Day | Turks and caicos islands | Public Holiday |
| Fri, May 31 | World No Tobacco Day | - | International |
| Fri, May 31 | Royal Brunei Armed Forces Day | Brunei | Public Holiday |
| Fri, May 31 | Lailat al-Qadr | Multiple [Show] | Multiple Types |
| Fri, May 31 | Canaries day observed | Spain (Canary Islands) | Local Holiday |
| Fri, May 31 | Day of Castile-La Mancha | Spain (Castile-la Mancha) | Local Holiday |
