For the 10th year in succession at the Circuit de Catalunya, the driver who started on pole position took the chequered flag as winner.
After 66 laps in the Catalan sunshine, Webber crossed the line a massive 24 seconds clear of Ferrari's second placed Fernando Alonso.
"It was a fantastic result and I'm absolutely thrilled," he said after his third career win.
Spaniard Alonso, celebrating his first home race for the Italian team, inherited a crowd-pleasing runner-up position when McLaren's hard-charging Lewis Hamilton crashed out with a suspected suspension failure on the penultimate lap.
Red Bull's Sebastian Vettel, who had started on the front row alongside Webber, finished third despite suffering brake problems.
Seven-times world champion Michael Schumacher was fourth, the best result so far of the 41-year-old's comeback season, with McLaren's Jenson Button unable to find a way past and forced to settle for fifth.
Button, Hamilton's team mate and reigning world champion, stayed top of the standings with 70 points to Alonso's 67 after five of the season's 19 races. Ferrari's Brazilian Felipe Massa was sixth, Germany's Adrian Sutil seventh for Force India and Poland's Robert Kubica eighth for Renault.
Williams returned to the points with Brazilian Rubens Barrichello in ninth place and local youngster Jaime Alguersuari took the final point for Toro Rosso at his home track.
Sutil finishes seventh
Adrian Sutil’s seventh place finish brought Force India back among the points again but Hispania driver Karun Chandhok’s hopes of a third successive finish were dashed after a tangle with Toro Rosso’s Jamie Alguersuari.
Sutil drove an immaculate race, jumping from his 11th place in the starting grid to eighth, which he defended with all his might and guile to stave off the consistent challenge from Renault’s Robert Kubica.
In lap 29, Alguersuari drove across the nose of Karun’s car, which eventually invited a drive through penalty. Karun had to pull up his car after 31 laps.
