Perhaps you are of the opinion that adults don't matter to Charlie Brown and his friends. You undoubtedly recall the "waah wah wah, wah wah wah waah" sounds of Charlie Brown's teacher and his parents. Perhaps you've seen the Thanksgiving cartoon where Charlie complains that he'll need help cooking the turkey because he only knows how to cook cold cereal. It might be that you've seen these things and you're lead to the conclusion that there are no real adults in the world of the Charles M. Schulz and his Peanuts gang. You, of course, would be wrong.

Charlie Brown's parents may remain unnamed in the series. They may have not spoken a single line in any of the movies. They do, however, exist. His father is a barber, his mother a housewife. Both have made off-screen appearances in the comic strip to call him here or there. Perhaps a little late in the game, but the June 20, 1993 comic strip even focused on Charlie's dad playing with Snoopy." 1

One of them, apparently, has a sister. Charlie and his sister, Sally, have both made reference to their Aunt Marian. More than that? We do not know.

I am happy to additionally report that while googling Chuck's parents for more information, I found that the band Dishwalla2, of "Counting Blue Cars" fame, actually have a song called "Charlie Brown's Parents." The song has little to do with the titled characters; it seems to refer instead to that infamous "wah wah" trumpet sound adults make in the comic strip. The closest thing to a reference is: "It feels like I'm talking to... Charlie Brown's Parents."

1Information from the Peanuts FAQ, written and maintained by Derrick Bang. Visit the website for more information.
2Song composed by Scott Alexander et al, released by Dishwalla on the album Pet Your Friends in 1995.