Workers at two Boston-area Starbucks seek to unionize after a win in Buffalo.

Days after Starbucks employees in Buffalo formed the only union at a company-owned store in the United States, workers at two Boston-area Starbucks filed for union elections with the National Labor Relations Board.

The filing, which was made on Monday, suggested that the victory in Buffalo could lead to a wider unionization push by employees, known as partners, at the nearly 9,000 stores owned by the company nationwide.

“We believe that there can be no true partnership without power-sharing and accountability,” the workers said in a letter to Starbucks’ chief executive, Kevin Johnson. “We are organizing a union in Boston because we believe that this is the best way to contribute meaningfully to our partnership with the company.”

A company spokesman declined to comment about the new filings.

The workers are seeking to join Workers United, an affiliate of the giant Service Employees International Union, which also represents the newly unionized employees in Buffalo.

On Thursday, the labor board announced the results of elections at three Buffalo-area stores, which workers had petitioned for in August. In addition to the store where the union won, workers at a second store voted down the union, though Workers United has indicated that it intends to formally object to the result. The union was leading at a third store where the results are still unresolved because of several ballots whose eligibility is being challenged by the union.

Workers at the two Boston-area stores began circulating union cards shortly after the Buffalo results were announced, according to two of the workers. They are seeking to hold two elections — one at each store.

Employees at three other Buffalo-area stores filed for union elections in November, as did employees at a store in Arizona. It is unclear when those elections or the elections in Massachusetts will take place.

Union supporters in Buffalo said that Starbucks workers around the country had contacted them over the past few months to say they were following the campaign closely and were also interested in unionizing.

Starbucks has argued to the labor board that all store employees in a market should vote in a single election rather than on a store-by-store basis. The board last week denied the company’s appeal of a decision allowing employees at the three Buffalo stores to vote separately.

Starbucks employees involved in the Buffalo organizing campaigns have cited issues with staffing and training, which some say worsened during the pandemic, but have also emphasized that the motivation for organizing extends beyond any particular policy. They have said they are seeking greater say in how stores are run.

Starbucks worked hard to defuse the union campaign in Buffalo, sending managers and company officials from out of town to work alongside employees and question them about their stores. Starbucks has said its intention was to help fix operational issues and that it has taken similar steps in stores around the country since the spring. Several employees who support the union said they felt intimidated and monitored by these officials.