By Heather Haddon

Starbucks Corp. said it would make T-shirts bearing the "Black Lives Matter" slogan available to employees, reversing an earlier directive not to display the slogan on their person at work.

The coffee chain said Friday that it would distribute 250,000 T-shirts bearing social slogans including "Black Lives Matter" and "It's not a moment, It's a movement" to employees at company-owned stores in the U.S. and Canada. Until they arrive, Starbucks said baristas could wear their own attire in support of the social movement.

"These are alarming, uncertain times and people everywhere are hurting. You've told us you need a way to express yourself at work," executives including Chief Operating Officer Roz Brewer and Rossann Williams, president of the U.S. company-operated business and Canada, wrote to employees. "We trust you to do what's right."

Starbucks's shift reflects the decisions facing big businesses navigating calls to support racial justice amid the national outcry stemming from George Floyd's killing, as well as to devote more attention and funding to increasing diversity and tolerance within their workplaces. Like Starbucks, many companies are also wrestling with how to allow employees to express their views without potentially alienating some customers.

Two employees at a Whole Foods Market in Bedford, N.H. were asked to take off masks with "Black Lives Matter" written on them last Saturday and instead put on masks that complied with the company's dress code, a spokeswoman said. Whole Foods Market's dress code prohibits slogans, messages or logos that aren't company-related, the spokeswoman said. One employee accepted the mask while the other refused and both later protested outside the store, said Whole Foods, which is owned by Amazon.com Inc.

Earlier in the week, Starbucks told employees that the company had a longstanding policy against buttons or pins that advocate for a political, religious or personal issue, according to a memo viewed by The Wall Street Journal.

The company said personal clothing and pins that referred to the movement could send the wrong message. "There are agitators who misconstrue the fundamental principles of the Black Lives Matter movement, and in certain circumstances, intentionally repurpose them to amplify divisiveness," the memo stated.

For some Starbucks employees, not being able to wear personal displays of their support for the issues of racial injustice at work was upsetting. Starbucks has official pins to wear for gay pride month in June, for example. One New York barista said she put a fist and a reference to Black Lives Matter on her nametag, given her strong convictions and disappointment at being unable to vocalize them at work. She said her supervisor let her keep them and inquired about her well-being.

In response to the killing of Mr. Floyd in police custody late last month, Starbucks held a listening session for employees and has indicated its support for protesters on social media. Starbucks said in the memo earlier this week that they were discussing how to further support black leaders.

"We know your intent is genuine and understand how personal this is for so many of us," the memo said.

The nationwide discussion sparked by the killing of Mr. Floyd and police violence more broadly comes as the Seattle-based chain is limiting employee hours to reflect its pared-back U.S. operations due to the coronavirus pandemic. The company is also speeding a shift to some smaller stores oriented toward takeout orders rather than in-store service.

This week, U.S. company workers were to decide whether to remain working with fewer hours, take a leave of absence or resign.

On Wednesday, Starbucks said it expected lost sales due to the pandemic would cause revenue to decline by $3 billion to $3.2 billion in its current third quarter.

Starbucks is known for providing benefits that include college assistance and expanded health care for those identifying as transgender. The chain closed all of its U.S. company-owned stores to hold antibias training in 2018 in response to an incident in Philadelphia where a store manager called the police in response to two black patrons who didn't purchase anything.

The incident was a challenge for Chief Executive Kevin Johnson's early leadership of the company, soon after he took over for longtime leader Howard Schultz. Mr. Schultz had sought for the chain to take up matters of race t hrough stickers placed on cups in the wake of events in Ferguson, Mo., in 2015, but later reversed course after criticism.

Jaewon Kang contributed to this article.

Write to Heather Haddon at heather.haddon@wsj.com