Three members of Britain's four-man team — Nick Skelton, Ben Maher and Peter Charles — rode clear rounds in a jumpoff to give the host team victory over the Netherlands. Saudi Arabia, a relative newcomer to the sport, was a surprising third.
Skelton, 54, fractured his neck in 2000 but returned to riding two years later.
"After I broke my neck, my goal was to get back to Athens in 2004 and then to get to here," Skelton said. "When you have a horse as good as Big Star, you look forward to getting up every day and riding him."
Competing in his fifth Olympics, Skelton said he was more nervous watching his teammates Monday than riding himself.
"I wish I could have gone four times," he said. "They've done great. I've got a wonderful horse, wonderful owners, it's a dream come true.
The last time Britain won an Olympic gold medal in show jumping was at Helsinki in 1952.
The four Dutch riders were still smiling broadly after silver was placed around their necks.
"We wanted to win gold, but we're very happy to win silver," said Dutch team rider Jur Vrieling.
Scores from the final round in the team competition were combined with scores from the first round Sunday.
Saudi Arabia held the lead with only one penalty point after the first round and four countries, including Britain and the Netherlands, were tied for second with four faults each.
The height of obstacles and the striding between fence combinations were made more difficult for Monday's final round, resulting in more dropped fence rails and a wide swing in the results.
The British and Dutch had eight faults each to put them into the jumpoff Monday. Saudi Arabia took bronze with 14, followed by Switzerland (16), Canada (26) and the United States and Sweden (28 points each).
Saudi Arabia has made a concerted effort the last three years to fund top horses and trainers for the country's riders, and it paid off.
"It means everything," said Saudi Prince Abdullah Al Saud, who rode Davos. "I am speechless."
The London Games mark the first time any women have competed on a Saudi team, with one each in athletics and judo. Rider Dalma Malhas had been touted for the Saudi show jumping team but her horse was injured.
"She was a bit unlucky in terms of the games here," said Saudi rider Kamal Bahamdan. "We're hoping that Dalma or any qualified female will participate in the next games."
The team competition also served as a qualifier for the individual show jumping event when the top 35 riders out of 75 entries advanced. The final individual round will be held Wednesday, when medals will be presented.
Skelton and Maikel van der Vleuten and Marc Houtzager, both of the Netherlands, are tied for first with no faults going into Wednesday's round. Edwina Tops-Alexander of Australia, Prince Abdullah Al Saud of Saudi Arabia and Ben Maher of Britain are tied for second with four faults each.
American Rich Fellers and Canadian Ian Millar are among a group of riders tied for 11th with eight faults each.
With the show jumpers having a day off Tuesday, the team dressage competition will conclude and medals will be presented.
Rafalca, co-owned by the wife of U.S. presidential hopeful Mitt Romney and ridden by Jan Ebeling, will compete for the United States in the final round of team dressage. Rafalca is ranked 30th and is not expected to move high enough to qualify for the final round of the individual dressage event Thursday.