The candy shells, each of which has the letter "m" printed in lower case on one side, surround a variety of fillings, including:
- milk chocolate
- dark chocolate
- crisped rice
- mint chocolate
- peanuts
- almonds
- orange chocolate
- coconut
- pretzel
- wild cherry
- peanut butter
Ever since the 1990's the Blue M&M campaign, M&M's introduced computer animated "spokescandies" in their television commercials.
- The cynical and sardonic "Red" (originally voiced by Jon Lovitz, thereafter Billy West), who is the mascot for milk chocolate M&M's
- The happy and gullible "Yellow" (originally John Goodman, thereafter J.K. Simmons), who is the mascot for peanut M&M's.
- The "cool one", Blue (originally Phil Hartman, thereafter Robb Pruitt) for almond
- The seductive Green (Cree Summer) for peanut butter, mint, and dark chocolate (Green is the only female M&M's mascot)
- The slightly neurotic Orange (Eric Kirchberger) for other types of M&M's in general, who was initially not named after his color (for a time when he was introduced, he was known as Crispy due to his being a mascot for the Crispy M&M's, which debuted around the same time.)
- Although brown M&Ms have been around since the beginning of the candy, no brown M&M "spokescandy" was included.