The National Labor Relations Board dismissed a charge filed by Starbucks against union organizers in Phoenix.
The federal agency said there was not enough evidence that pro-union workers had blocked entrances or intimidated customers during a rally in the spring.
Starbucks filed a complaint to the labor board in April claiming the pro-union workers violated labor law by threatening workers and customers.
But in a letter to the company, the regional director of the agency in Phoenix dismissed the charge. He said his investigation showed demonstrators remained on sidewalks.
On Monday, Starbucks said it will appeal the decision.