www.alphadictionary.com

Does anyone have an origin for this expression?

I thought it was from Aesop, but my Google search suggests it is not a particularly old phrase.

Thanks,

I've always heard as Be Careful what you wish for.
But that lends nothing to the discussion.

mark wishing-like-a-mad-chimp Bailey

According to this chap, Iit is an opening quote from the Monkey's Paw, which is a classic horror story apparently written by W.W. Jacobs,, first appearing in Harpers Monthly in 1902. The author attributed the saying to Anonymous.