A syndicated comic strip by cartoonist Arthur R. Momand which ran in American newspapers from 1913 to 1931. Originally, the title was to be "Keeping up with the Smiths", but Momand decided to change the name to "Joneses" just before first publication, giving us the cliché we still use today to describe neighborly competition.

Several sources list this as the true source of the phrase. I've heard of at least three other possible sources, mostly wealthy 19th century individuals named "Jones", but they all seem aprocryphal in comparison to the evidence supporting this source.