The last name of the family has only three times been revealed on the show. It is Wilkerson, as revealed in the pilot as the name tag Francis wears on his school uniform. There was also a joke that appeared in the original pilot script. In that script, Malcolm was walking to school when a neighborhood kid came running up shouting, "Malcolm, Malcolm, Malcolm. I was talking to my parents last night - I was listening to them talk, and what's your last name?" "Wilkerson, why?" Malcolm replied. "Oh. Who are the Pariahs?" said the other kid. The joke was eventually cut, and the show's writers subsequently decided never to reveal the family's last name, but it would seem they forgot about Francis's name tag. In the company picnic episode, Hal also refers to them as 'the Wilkersons'. Jennette McCurdy (Daisy Wilkerson [Dewey]) was credited as Wilkerson revealing the last name of the family was Wilkerson.