Snoopy's mother is one of the few Peanuts characters to have first appeared in an animated television special before later appearing in the comic strip, (the only other one being Snoopy's brother Andy). Snoopy's mother, named as Missy in the special, is seen in a flashback in Snoopy's Reunion, which was first televised on May 1, 1991. Her first appearance in the comic strip is in the strip from July 26, 1996, in which she travels on a World War I troopship to visit Spike, (in the infantry), who is ill.
- In the TV special, Snoopy's Reunion, Snoopy's mother is given the name Missy, and in the iPad app Snoopy's Street Fair, his father is given the name Baxter. However, neither of these names have been given in strip, and therefore, cannot be considered canon.