The accident occurred over Cappadocia's sculpted rock formations when one balloon collided with the basket of another balloon above and crashed to the ground, the governor of Nevsehir province, Abdurrahman Savas, told Anatolia news agency.
"The lower balloon was torn and fell quickly," he said, citing witness accounts.
Savas said two Brazilians, 71-year-old Maria Luiza Gomes and 65-year-old Mariua Rosas, "lost their lives", while most of the injured suffered broken bones.
Earlier, a provincial official had told AFP that one of the people that died was a Spanish national. He told the Turkish news agency the tourists were part of a group of South Americans vacationing in the region.
Also Read
Ballooning has become increasingly popular in recent years in Turkey.
Several companies offer hot-air balloon rides over Cappadocia, which is a major tourist attraction with its cone-shaped rock formations, rock-carved underground cities and early Christian churches.
The owner of the hot-air balloon that went down said he was "shocked" by the tragedy but said the pilot had taken all the necessary safety measures. "These types of flights have been happening safely in Cappadocia for 20 years," Halil Uluer told the news agency.
The accident comes three months after a balloon exploded in Luxor, Egypt, killing 19 people on February 26.