The tweet sent Tuesday was part of a promotion tied to Queen Elizabeth II's Diamond Jubilee and aimed primarily at the United Kingdom, not the Republic of Ireland, The Guardian reported. It appeared to show ignorance of the complicated history of Britain and its neighbor in the British Isles.
Starbucks tweeted two apologies.
"We apologize to all our customers and followers on Twitter in Ireland and hope that they will forgive our mistake," the second one ended.
Some followers responded with a dash of humor: "Right now someone in Starbucks Ireland is wishing there was a Twitter version of the memory wipe thing from Men In Black."
At least one said he would drink no more Starbucks coffee until the company apologized.
Nike made a similar gaffe with a St. Patrick's Day shoe named the Black and Tan, the Guardian said. The company was thinking of the drink made by mixing Guinness Stout and pale ale, but for many in Ireland the Black and Tans are still the British paramilitary force that became hated during the fight for independence 90 years ago.