Thousands of loyal Market Basket employees and customers are at Stadium Plaza in Tewksbury this morning for the biggest rally yet since the firing of CEO Arthur T. Demoulas.

The location is the supermarket chain’s headquarters at the corner of a Tewksbury Market Basket parking lot at the Stadium Plaza Shopping Center.

Workers — and, in many cases, their families — brought homemade signs to show support of Arthur T. One read that the loyal employees are “not gonna give up the fight.”"

A revolt by workers at the supermarket chain has led to empty store shelves, angry customers and support for a boycott from more than 100 state legislators and mayors.

The employees are demanding the reinstatement of beloved former CEO Arthur T. Demoulas, who workers credit with keeping prices low, treating employees well and guiding the company's success.

The New England grocery store chain is embroiled in a family feud featuring two cousins who have been at odds for decades.

While earlier squabbles between Arthur T. Demoulas and Arthur S. Demoulas were fought in courtrooms, this dispute has spilled into Market Basket stores.

For the past week, warehouse workers have refused to make deliveries to Market Basket's stores, leaving fruit, vegetable, seafood and meat shelves empty. Workers have held huge protest rallies and organized boycott petitions through social media, attracting thousands of supporters.

Customers are defecting to other grocery stores. In some cases, customers have taped receipts from competitors to Market Basket windows.

Despite threats by new management to fire any workers who fail to perform their duties, some 300 warehouse workers and 68 drivers have refused to make deliveries. So far, eight supervisors have been fired. Massachusetts Attorney General Martha Coakley, who is running for governor, and New Hampshire Gov. Maggie Hassan have publicly supported the employees.

Market Basket stores have long been a fixture in Massachusetts. The late Arthur Demoulas — grandfather of Arthur S. and Arthur T. and a Greek immigrant — opened the first store in Lowell nearly a century ago. Gradually, Market Basket became a regional powerhouse, with 25,000 employees and 71 stores in Massachusetts, New Hampshire and Maine.

The feud dates back to the 1970s, but the most recent round of infighting began last year when Arthur S. Demoulas gained control of the board of directors. Last month, the board fired Arthur T., sparking the current uprising.

Workers are fiercely loyal to Arthur T., and many are distrustful of Arthur S. and two co-chief executives who were brought in from outside the company: Felicia Thornton, a former executive of the grocery chain Albertsons, and Jim Gooch, former president and chief executive at RadioShack Corp.

Arthur T. on Wednesday offered to buy the company for an undisclosed amount.

Gooch and Thornton declined to comment.

The company's board of directors is meeting today in Boston.

Herald Wire Services contributed.