May
- ALS Awareness Month (United States)
- Asian American and Pacific Islander Heritage Month
- Brain Tumor Awareness Month (excluding United Kingdom)
- Flores de Mayo (Philippines)
- Haitian Heritage Month
- Jewish American Heritage Month (US)
- Lyme Disease Awareness Month
- May devotions to the Blessed Virgin Mary
- Mental Health Awareness Month[26]
- National Bike Month
- National Military Appreciation Month
- National Foster Care Month
- National Guide Dog Month (2008, 2009)
- National Pet Month (United States)
- National Smile Month (United Kingdom, May and June)
- National Stroke Awareness Month
- South Asian Heritage Month (Ontario, Canada)
- Zombie Awareness Month