What is National Mantra Day? National Mantra Day is celebrated on May 1 each year. The Day was created so participants can experience how self-reflection along with the collective power of sound can favorably change themselves and the world! You are encouraged to give your favorite mantras throughout the day!​ ​What is a Mantra? A mantra is a short, spoken prayer consisting of a repeated word or group of words that invoke a particular aspect or quality of God. The word