NEW YORK — Put down that turkey leg. It’s time to shop. No, really.

Stores typically open in the wee hours of the morning on the day after Thanksgiving known as Black Friday, named for the period when stores traditionally turn a profit for the year. But Black Friday openings have crept earlier and earlier over the past few years. Now, stores from Walmart to Toys R Us opened their doors on Thanksgiving evening, hoping Americans will be willing to shop soon after they finish their pumpkin pie.

Walmart Stores Inc. had early bird shopping specials at 8 p.m., two hours earlier than a year ago. Target Corp. opened its doors at 9 p.m. on the holiday, three hours earlier than last year. Sears, which didn’t open on Thanksgiving last year, opened at 8 p.m. Thursday and will stay open until 10 p.m. on Black Friday. And Toys R Us opened at 8 p.m., an hour earlier than last year.

It’s an effort by stores to make shopping more convenient for Americans, who still face economic uncertainty. Many shoppers are worried about high unemployment and a package of tax increases and spending cuts known as the “fiscal cliff” that will take effect in January unless Congress passes a budget deal by then. At the same time, Americans have grown more comfortable shopping on websites such as Amazon.com, where they can get cheaper prices and buy from the comfort of their home or office cubicle.

Early data from IBM Smarter Commerce show that as of noon EST, online sales for Thanksgiving are up 14.3 percent from last year, with just over a quarter of consumers using a mobile device to visit a retailer’s site, up from 15.8 percent in 2011.

That has put pressure on brick-and-mortar stores, who can make up to 40 percent of their annual revenue during the two-month holiday shopping season, to compete. That’s becoming more difficult: the National Retail Federation, an industry trade group, estimates that overall sales in November and December will rise 4.1 percent this year to $586.1 billion, or about flat with last year’s growth. But the online part of that is expected to rise 15 percent to $68.4 billion, according to Forrester Research.

As a result, brick-and-mortar retailers are trying everything they can to lure consumers into stores by making shopping as easy as possible. In addition to expanding their hours into Thanksgiving, many are offering free layaways and shipping, matching the cheaper prices of online rivals and updating their mobile shopping apps with more information.

Michael Prothero, 19, and his friend, Kenny Fullenlove, 20, have been camped outside a Best Buy store in Toledo, Ohio, since Monday night, waiting to get 40-inch televisions, some video games and a low-priced tablet computer mainly for relatives. They came early to make sure they got the deals, even though the next person in line didn’t arrive until almost 24 hours later.

“Better safe than sorry,” Prothero said.

They know they’ll miss Thanksgiving dinner with their families, but say it’s worth it.

“Every retailer wants to beat everyone else,” said C. Britt Beemer, chairman of America’s Research Group, a research firm based in Charleston, S.C. “Shoppers love it.”

Retailers are hoping that the Thanksgiving openings will draw shoppers who prefer to head to stores after their turkey dinner rather than braving the crowds early the next morning. Overall, about 17 percent of shoppers plan to take advantage of Thanksgiving hours, according to the International Council of Shopping Centers-Goldman Sachs survey of 1,000 consumers conducted from Nov. 15 to Nov. 18. Last year, that figure was 16 percent. For Black Friday, traditionally the busiest shopping day of the year, 33 percent intend to shop that day, slightly down from 34 percent in 2011.

For 11 people in a four-tent encampment outside a Best Buy store near Ann Arbor, Mich., a super deal on a 40-inch Toshiba LCD television is worth missing Thanksgiving dinner at home.

Jackie Berg, 26, of Ann Arbor, arrived first with her stepson and a friend Wednesday afternoon, seeking three of the televisions. On Black Friday, Best Buy is selling them for $179, $240 less than the normal price, so Berg would save more than $700.

It’s her first time camping out for the specials, and she’s not sure she will do it again. Relatives will bring her some holiday dinner, but she’ll miss eating her dad’s stuffing right as he cooks it.

“We’ll miss the actual being there with family, but we’ll have the rest of the weekend for that,” she said.

But not everyone likes the idea of Turkey Day shopping. Some retailers that are opening on Thanksgiving face criticism from workers who complain that the holiday should be a time for everyone to spend with their family.

A New York-based union-backed group of retail workers called Retail Action Project planned protests in the Manhattan borough of New York City on Thanksgiving in front of several stores, including AnnTaylor, Forever 21 and others that are opening at midnight on Black Friday and earlier.

“It shows that the companies are not valuing their workers. They’re looking to their workers to squeeze out more profits,” said Carrie Gleason, director of Retail Action Project.

Walmart, the world’s largest retailer, has been one of the biggest targets of protests against holiday hours. The issue is part of a broader campaign against the company’s treatment of workers that’s being waged by a union-backed group called OUR Walmart, which includes former and current workers. It’s staging demonstrations and walkouts at hundreds of stores on Black Friday.

Mary Pat Tifft, a Walmart employee in Kenosha, Wis., who is a member of OUR Walmart, started an online petition on signon.org that has about 34,000 signatures.

“This Thanksgiving, while millions of families plan to spend quality time with their loved ones, Walmart associates have been told we will be stocking shelves and preparing sales starting at 8 p.m.,” she wrote on the site.

But retailers say they are giving shoppers what they want. Dave Tovar, a Walmart spokesman, said that the discounter learned from shoppers that they want to start shopping right after Thanksgiving dinner. Then, they want to have time to go to bed before they wake up to head back out to the stores.

Still, Tovar said that Walmart works to accommodate its workers’ requests for different working hours.

“We spent a lot of time talking to them, trying to figure out when would be the best time for our events,” he said.

Kathee Tesija, Target’s executive vice president of merchandising, said Target’s 9 p.m. opening struck “a perfect balance” for its customers. When asked whether it’s faced any criticism from Target employees, she noted that the chain also works with workers to accommodate their needs. But, ultimately the company serves the customer.

“We thought long and hard about when the right opening time would be,” she said, adding that Target “wants to make sure we are competitive.”