Red Bull have now taken nine poles in a row dating back to the end of last year, the first team to do so since McLaren in 1998.
Their continued dominance seemed to make a mockery of suggestions that the champions could suffer from a clampdown by the governing body on the use of engine electronics and exhaust gases to influence performance.
The 23-year-old German, who has finished in the top two in every race of the season so far, will be chasing his sixth win of the year around the Mediterranean port city's streets.
Vettel's fastest lap of one minute 36.975 seconds was the fastest ever in Valencia and made the pole a foregone conclusion with minutes still to run in the session.
"I think, mate, we've said it enough. We've come here and we didn't expect any different," said Webber, whose sole pole of the season so far came in Barcelona in May when Red Bull also swept the front row, of the rule change.
"Some other teams spoke a lot about it, maybe even some people in our team spoke a bit that maybe technically are not completely on top of things, but in the end we've just got on with our job, basically."