Shipments climbed 3.2 percent, below the 5.1 percent growth that had been projected, the research firm said. The industry shipped 91.8 million units in the period, compared with almost 89 million last year, Gartner found.

“Back-to-school PC sales were disappointing in mature markets, confirming that the consumer PC market continues to be weak,” Mikako Kitagawa, an analyst for Stamford, Connecticut- based Gartner, said in a statement. “The popularity of non-PC devices, including media tablets, such as the iPad and smartphones, took consumers’ spending away from PCs.”

Hewlett-Packard Co., which is considering whether to spin off its PC business, remained the industry’s top seller, accounting for 17.7 percent of the global market. Lenovo Group Ltd. ranked No. 2 for the first time, boosted by a joint venture with NEC Corp. and aggressive marketing, Gartner said. Dell Inc. was third, with 11.6 percent.

In the U.S., Hewlett-Packard was the largest, accounting for 28.9 percent, and Dell was second with 21.9 percent, Gartner said. Apple, based in Cupertino, California, was the third- biggest seller, accounting for 12.9 percent of the market, up from 10.8 during the same period a year earlier, Garter said.