In this week’s planned events, OUR Walmart, which stands for Organization United for Respect at Walmart, is enlisting a broad range of allies, arranging fliers and letters that community, church and civil rights groups can use to publicize the Black Friday protest. OUR Walmart has even prepared remarks that it is suggesting members of the clergy might use in prayer, “to call upon the world’s largest corporation to treats its workers with justice and fairness.”

Many of those workers assert that Wal-Mart pays poverty-level wages, assigns too few hours a week and retaliates against protesting employees.

“I will be protesting because there has been retaliation from the company — they have fired people, they have reduced people’s hours for speaking out,” said Greg Fletcher, an electronics department employee at a Walmart in Duarte, Calif.

David Tovar, a spokesman for Wal-Mart, said the company prohibits retaliation, and respects the rights of associates to express their views. But, he added, “if people repeatedly have unexcused absences, if they purposefully disrupt the store, or create an unsafe working condition for our customers and associates, those issues will be addressed” in accordance with company employment policy.

In the filing with the labor board, the company said that the continuing protests were illegal because under the National Labor Relations Act, a union seeking recognition can picket for a maximum of 30 days. After that, it must either stop picketing or take a formal unionization vote. The company says the United Food and Commercial Workers Union is behind the protests and has exceeded the 30-day limit.

“Many of these ongoing tactics being orchestrated by the U.F.C.W. are unlawful,” Mr. Tovar said. “The United Food and Commercial Workers Union and its subsidiary, OUR Walmart, have been conducting illegal pickets and other demonstrations for several months now, clearly beyond what the law allows.”

Officials with the union and OUR Walmart say the demonstrations and picketing aim to protest what they call illegal labor practices by Wal-Mart, specifically retaliating against protesting workers, and in no way aim to seek union recognition, as the company asserts.