It was not immediately clear how 3G would be licensed or sold, and a cabinet statement did not elaborate on when any such decision would be fully implemented.
But the announcement was quickly welcomed by the country's second-biggest mobile operator.
"The General Secretariat of the Council of Ministers announces the approval of granting mobile phone companies working in Iraq the right to use third-generation frequencies," a cabinet statement said.
"The purpose of this... Is to provide services with high quality."
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In Iraq, however, users have been stuck on 2G networks, despite mobile penetration relatively high at nearly 90 percent, and the government having launched a consultation in 2011 on implementing 3G services.
Customers can choose primarily between Zain, the Iraqi arm of the Kuwaiti operator of the same name, Asiacell, which is majority-owned by Qatar Telecom, and Korek.
"We have been waiting for it," Asiacell Chief Executive Amer Sunna told AFP by phone from the company's base in the Kurdish city of Sulaimaniyah. "This is exciting news for us."
Older 2G technology allows mobile phones to make and receive calls and text messages and browse basic websites, but 3G dramatically increases the capacity, or bandwidth, of a network, allowing users to browse more complicated websites faster.
While mobile phones in much of the Western world and several countries in Asia and the Middle East largely operate on 3G technology, some countries have moved on to even faster 4G wireless standards.
These allow customers to download still larger files and view videos on demand, all at varying fees.
"I mean, 3G? You know, 5G is under testing and maybe commercial launch in China," he told AFP.
"It's been a while. I think frustration is there. ... Today, you see the penetration rate hitting 90 percent, and we're still on 2G."
With 3G-capable phones able to handle data and applications, popularised first by Apple's iPhone and increasingly in use by so-called "smart phones", mobile operators are able to charge for a wider array of services than simply calls and text messages.