The magazine, Teen Vogue, is ready to begin promoting Aug. 11 as a national day for back-to-school shopping. Back-to-School Saturday will offer young shoppers — and the parents who often pay the bills — sales, free samples and events in stores and malls.

Teen Vogue has two dozen advertisers taking part, all of them reliant on the back-to-school season for revenue. The participants will include Aéropostale, American Eagle Outfitters, Express, Guess, H&M, Maybelline New York, Pacific Sunwear of California, Quiksilver, Staples and Vans. Four brands sold by Procter & Gamble, the nation’s largest advertiser, will be involved: Cover Girl, Olay, Pantene and Tampax.

Back-to-School Saturday will be promoted in the typically enthusiastic Teen Vogue tone of voice. For instance, ads and posters will exhort, “Get ready, get set, get shopping!” And social media will, of course, play a big role; Teen Vogue has already called dibs on a hashtag, #btss.

“We’re trying to create a moment of imagination and motivation,” said Jason Wagenheim, vice president and publisher of Teen Vogue, part of the Condé Nast Publications division of Advance Publications. “We saw it as a real opportunity, because for our girls, back-to-school is as important as” the Christmas shopping season, he added.

Mr. Wagenheim acknowledged that the back-to-school shopping period “is a very random 8 to 12 weeks that starts early in the South and later in the North.” But research suggested that shopping for school supplies, clothing and other merchandise “seems to peak in the second and third week of August,” he said, so the Aug. 11 date was selected as one that could be turned into “a galvanizing moment.”

Alison Corcoran, senior vice president for retail marketing at Staples, echoed Mr. Wagenheim.

Although “the season starts in June in some markets and goes all the way to the third week of September in Manhattan,” Ms. Corcoran said that designating Aug. 11 as a special occasion “is putting a stake in the ground, saying, ‘Here’s a day you can rally around.’ ”

And “for value-conscious parents,” said Ms. Corcoran, who described herself as “a mom of four,” it is “great to know there’s a day with the best of the best deals.”

As part of Back-to-School Saturday, she added, Staples will promote, among other offers, its annual Back to School Savings Pass, which costs $10 and offers 15 percent off “all your school supplies for the rest of the season.”

Mr. Wagenheim said he was not daunted by how chockablock the shopping calendar already is with days intended to stand out from the everyday. “Kids are looking for something to do,” he said, “and back-to-school is important to them.”

And “we look to our big sisters from Vogue,” Mr. Wagenheim said, who introduced in 2009 a national shopping event called Fashion’s Night Out. The Vogue initiative has grown larger each year, expanding internationally, and this year is Sept. 6.

Consumers are becoming “increasingly interested in event-based shopping,” said Gary H. Schoenfeld, chief executive at Pacific Sunwear, who recalled how he was “up all night on Black Friday in three or four of our stores, and customers were having a blast.”

“Three o’clock in the morning felt like 8 o’clock at night, as people were with friends and having a great time shopping,” Mr. Schoenfeld said. “The idea of Teen Vogue trying to introduce something like that for back-to-school is a fun idea; why not be a part of it?”

Deborah Marquardt, vice president for media and integrated marketing at Maybelline New York, part of the L’Oréal USA division of L’Oréal, said that for Teen Vogue’s target generation, “shopping is like a sport.”

Back-to-School Saturday represents an “opportunity to get out in front of this key audience,” she added, in a relevant way that “gives shape and focus to something that’s already existed, elevating it, event-izing it and celebrating it.”

“If it doesn’t provide anything of value,” Ms. Marquardt said, consumers will not respond. “But they’re going to get samples, and they’re going to get offers, and there’ll be a fashion show at the Grove,” she added, referring to a mall in Los Angeles, “where 10-to-15,000 are expected.”

Teen Vogue offered advertisers a chance to participate in Back-to-School Saturday if they agreed to do more business with the magazine, in some combination of print and/or digital spending.

For its part, Teen Vogue is spending hundreds of thousands of dollars on the initiative, an amount similar to what the magazine has spent on previous efforts like Teen Vogue Fashion University.

Mr. Wagenheim said, “Our long-term hope is that it becomes part of the retail calendar, like Black Friday.”

The August issue of the magazine, on sale on July 3, will have a back-to-school theme, and there will be additional content on teenvogue.com. There are plans for an iPhone app, called Teen Vogue Insider, timed for Back-to-School Saturday.