What is the origin of "Dont air your dirty laundry in public"

It means ..keep your private stuff private....
Don't talk about your problems, or your family secrets.

I agree with the answers given... and I also think this is good advice that should be taken by certain attention-seekers around here tonight.

It is originally French. Has to do with people back when they used to hang out their clothes to dry and some of them were "intimates" etc. Something close to that without taking 30 minutes to look it up.

I remember when I was small my grandmother said if you don't want your business told leave it in the basket - if you hang it out everyone will see it - ( keep it to yourself )

dont bump your gums about your problems to everyone, more than likely they don't care anyway.

Air your dirty laundry in public:

"Air your dirty laundry (or linen) . . ." means to tell scandalous or unflattering stories about yourself, to reveal things from your private life that people usually don't want others to know. Sometimes the phrase is used when the privacy that's invaded is the privacy of a couple, not an individual. For example, a husband might say to friends "Mary and I got so mad at each other last Friday that we didn't speak all weekend," at which his wife says "John, let's not air our dirty laundry in public." It's a metaphor. People would normally find it embarrassing if others saw their clothes and sheets and towels that need washing, and if they're not embarrassed, then the witnesses will be. The same goes for making inappropriate confessions and revealing unpleasant family secrets.

http://www.phrases.org.uk/bulletin_board/26/messages/837.html

Don't wash your dirty laundry in public:

(UK) People, especially couples, who argue in front of others or involve others in their personal problems and crises, are said to be washing their dirty laundry in public; making public things that are best left private. (In American English, 'don't air your dirty laundry in public' is used.)

http://www.usingenglish.com/reference/idioms/d.html

dirty linen - Also called dirty laundry [Origin: 1945–50]

personal or private matters that could cause embarrassment if made public; "You didn't have to air our dirty linen to all your friends!"

Personal affairs that could cause embarrassment or distress if made public; "Let's not air our dirty laundry in front of our guests. Also called dirty linen."

personal matters that could be embarrassing if made public.

http://dictionary.reference.com/browse/dirty%20laundry

1) In French, we use:
"Il faut laver son linge sale en famille.
- Idiomatic translation: Don't air your dirty laundry in public.
- Literal translations: One needs to wash one's dirty laundry with family around."
Source:
http://en.wikiquote.org/wiki/French_proverbs


2) This saying has been attributed to Napoleon.
For instance here:
"Elle semblait avoir pris pour
devise, en tant que nation, le mot énergique que
Napoléon disait dans un sens plus restreint :
qu' il faut laver son linge sale en famille ."
Translation: It [Spain] seemed to have taken for
devise, as a nation, an energetic word that
Napoleon said in a more restricted sense:
that it is necessary to wash its dirty linen in the family.
Source:
http://gallica.bnf.fr/ark:/12148/Document/CadresPage.jsp?O=NUMM-89617&I=1&J=null&M=tdm