Could these executives just ask their children for tech tips? Sure. But workplace programs allow executives to peer into the future of their industry and bond with a junior colleague simultaneously, with minimal embarrassment.

Reverse mentoring — another name companies give to younger people training older workers — is not a new concept. Jack Welch, while the chief executive of General Electric in the 1990s, required 500 of his top managers to pair up with junior workers to learn how to use the internet. But executives are especially eager to learn from millennials, whose dominance in Silicon Valley has given older workers a fear of obsolescence.

An entire cottage industry now peddles advice to youth-obsessed executives, with books like “Understanding Millennials” and events like “Millennial Week,” a two-day festival meant to “promote and present ideas reflecting the impact of Generation Y on culture and society.” Millennial consultants now advise companies like Oracle, Estée Lauder and HBO, charging as much as $20,000 per hour to give executives advice on marketing their products to young people. Over all, American organizations spent about $80 million on “generational consulting” last year, according to Source Global Research, a firm that studies the consulting industry.

Compared with the prospect of shelling out thousands of dollars for one of those outside consultants, many executives prefer the alternative of using the young people already on their payroll.

“It’s a pretty smart thing for them to do,” said Malcolm Harris, the author of “Kids These Days,” a forthcoming book about millennials and the economy. “If you can’t get a 25-year-old to run your company, you can at least tell people your C.E.O. is talking to 25-year-olds.”

Tiffany Zhong, 20, began mentoring Kara Nortman, 41, a partner at the venture capital firm Upfront Ventures, after Ms. Nortman asked her for advice on dealing with a new generation of tech entrepreneurs.