WASHINGTON — Retail apparel prices fell for the third consecutive month in November, as overall consumer prices remained flat, the U.S. Labor Department reported Tuesday in its Consumer Price Index.

Prices on all apparel sold at retail fell a seasonally adjusted 0.4 percent last month. Women’s retail apparel prices rose 0.2 percent, while prices for men’s apparel declined 1.5 percent. Girl’s apparel prices dropped 3.2 percent, while boy’s apparel prices were up 0.8 percent.

Within the women’s category, retail prices for outerwear fell 0.6 percent, while prices for suits and separates dropped 0.5 percent. Prices for dresses rose 2.4 percent, while prices for the broad category that includes underwear, nightwear, sportswear and accessories gained 1 percent.

In men’s wear, prices for pants and shorts decreased 7.3 percent, as prices for furnishings fell 0.4 percent. Prices for the combined category of suits, sport coats and outerwear increased 1.7 percent, while prices for shirts and sweaters rose 0.7 percent.

“This was the third month in a row that apparel prices fell,” said Jeet Dutta, senior economist at Moody’s Analytics. “It seems that at the start of the holiday shopping season the [sales] numbers weren’t so good, and so it is possible that retailers got a little worried about the kind of volume they might be doing and therefore discounted heavily.”

Overall CPI was flat in November, after declining 0.1 percent in October. The core index, which excludes volatile food and energy prices, was up 0.2 percent last month.

“Many retailers introduced heavy dosages of price discounting in order to lure shoppers into stores,” said Chris G. Christopher Jr., director of consumer economics at IHS Global Insight. “Consumer goods prices excluding food and energy have taken a slight hit for three consecutive months. Retailers are hoping to increase revenue by more foot traffic and volume, while per-unit margins suffer.”

Christopher said IHS is forecasting a 3.2 percent increase in holiday retail sales over the previous year, for a total of $598 billion.

“This year’s growth is likely to be the weakest since 2009,” he said. “Black Friday week was not particularly stellar on the brick-and-mortar front, although cyber sales seem to be gathering momentum.”