Employees speak up at Wayfair, Google. Have Millennials killed being afraid of the boss?

Not happy with the leadership at your company?

You may not have to keep your mouth shut anymore. Gone are the days when speaking up got you automatically fired.

Employees, especially millennials, feel increasingly emboldened to publicly criticize their employers, organize protests and pursue change at the top on issues such as gender equality and immigration.

Among the latest examples: home goods seller Wayfair, and technology companies Google and Amazon.

Wayfair Walkout

Wayfair, the online furniture seller came under fire this week from its employees for selling goods to a contractor that supplied a migrant detention center.

Hundreds of Wayfair workers protested the company's actions Wednesday in Boston's Copley Square after CEO Niraj Shah dismissed calls to refuse to do business with contractors of border detention camps along the U.S.-Mexico border.

"We don't want our company to profit off of children being in concentration camps," said Madeline Howard, 29, a project manager at Wayfair, during the rally. "We want them to have a code of ethics that blocks orders like this from happening again."

Like the Wayfair employees, 38% of American employees say they've "spoken up to support or criticize" their employer's "actions over a controversial issue that affects society," according to a study on employee activism released in May by communications and marketing firm Weber Shandwick.

Millennials are particularly bold, with 48% saying they've spoken up, compared with 33% of Generation X and 27% of baby boomers.

"Being an employee is actually a great gift to change the industry for which you work. If you want to invoke change, the best way to do so is to go into the industry where you want to see the change and fight for it."

—Rebecca Sheppard, Amazon employee

"Employees, and particularly millennials, are very tied to the values of the organization and have expectations about their companies—and when they're frustrated, if their values are being violated, they speak up," said Leslie Gaines-Ross, chief reputation strategist of Weber Shandwick.

Executives are noticing as employees agitate for change.

Amazon Climate Change

At Amazon, some 8,000 employees concerned about climate change have signed onto Amazon Employees for Climate Justice. The worker group won the support of two independent shareholder advisory services for a proposal pressing Amazon to account for its emissions and has continued to advocate for action since the company and investors rejected the resolution in May.

Rebecca Sheppard, a senior product manager at Amazon who is active in Amazon Employees for Climate Justice, said "Amazon's paying attention"—based on the company's recent actions, including an announcement involving plans to cut emissions from 50% of packages.

"Being an employee is actually a great gift to change the industry for which you work," Sheppard said. "If you want to invoke change, the best way to do so is to go into the industry where you want to see the change and fight for it."

University of Michigan business professor Erik Gordon, who has taught management and marketing classes, said the shift is forcing executives to reconsider their approach to corporate activism.

In some cases, it's prompting companies and CEOs to make public statements about political issues before their workers demand action.

"Top management of most companies is at least two generations away from the younger workers," Gordon said. "Companies that have a larger proportion of younger workers are trying to get on offense and not play defense."

Following the Wayfair uproar, Bank of America announced this week that it would cease financing for operators of detention centers and private prisons. Bank of America said in a statement that it had been considering the move "for some time." JPMorgan Chase and Wells Fargo reportedly made similar announcements earlier this year.

For corporations, it's not always atruistic. There's a practical reason to speak up and take action on certain issues: They want to maintain the perception that they're a good place to work.

"Rather than sacrificing your morality or your beliefs, you can encourage the company you work for to address them in a way that keeps you satisfied with your employer, and companies that don't do that have a real with retention," Sheppard said.

Google Pride Parade

That doesn't mean employees who speak up are altogether immune to retribution.

A group of Google employees, who signed a petition posted to the blogging platform Medium urging San Francisco Pride to revoke Google's sponsorship of the group's June 30 parade, acknowledged that they could face punishment.

"We have considered the possibility that our employer will punish us for signing this letter, or that supporters of these very hatemongers will attack us personally, online or otherwise, simply for speaking out against them," the workers wrote. "Despite these risks, we are compelled to speak."

But with social media's amplification effect, workers who face retaliation have a viable outlet to fire back, unlike during the pre-internet age, when it would be virtually impossible to get attention without filing a lawsuit or getting traditional media coverage.

"With social media, certainly it can take on an incredible velocity, spreading the word," said Weber Shandwick's Gaines-Ross.

Yet it's personal interactions that ultimately drive change, said Amazon's Sheppard.

"Social media can help spread awareness, but really the catalysts for change are one-on-one connections," she said.

Expect more, said Michigan's Gordon.

"I think we're going to see more and more of these" movements, the business school professor said. "We have in the workplace people who were my students last year or five years ago—they are genuinely concerned about a lot of social issues and they think companies have social responsibilities that prior generations thought were not the business of businesses."