Starbucks faces its largest strike yet as thousands of nonunionized baristas will walk off the job on Thursday. The baristas are walking out in solidarity with thousands of Starbucks Workers United baristas to protest unfair labor practices at the coffee giant.

SWU said a one-day work stoppage will occur on Red Cup Day (Thursday), the biggest sales event of the season for the company. They said Red Cup Day is one of the most understaffed and most challenging days for baristas of the year.

“In addition to our nationwide ULP strike on the 16th, we’re also asking customers and allies to lead actions at Starbucks stores in their communities in solidarity with workers rising up for a fairer workplace,” the union said.

In an emailed statement, Oklahoma City employee Neha Cremin told Bloomberg, “Starbucks has made it clear that they won’t listen to workers, so we’re advocating for ourselves by going on strike.”

The union called the labor action “Red Cup Rebellion” and said thousands of nonunionized and unionized workers planned to walk out.