The quake struck 60 miles north of the Thai city, Chiang Rai
Tremors were felt as far away as Bangkok, almost 500 miles (800km) from the epicentre of the 6.8 magnitude quake.
An official in Burma warned there could be "many more casualties" in the town of Tarlay, close to the epicentre.
He confirmed 10 men, a boy and 13 women had already been killed by the disaster.
The shaking was also felt throughout China's southwest province of Yunnan, according to state-run China National Radio, but no casualties or structural collapses had been reported.
Some residents of the Vietnamese capital Hanoi also fled their homes in panic when the quake shook the city.
Nguyen Thi Hong Hanh, 36, who lives on the 10th floor of a highrise, said her husband noticed their pet fish shaking in their tank.
"We all rushed to the street. All the other people in the apartments also rushed out," she said.
The quake comes two weeks after Japan was hit by one of the biggest earthquakes on record.
Some residents of the Vietnamese capital Hanoi also fled their homes in panic when the quake shook the city.
Nguyen Thi Hong Hanh, 36, who lives on the 10th floor of a highrise, said her husband noticed their pet fish shaking in their tank.
"We all rushed to the street. All the other people in the apartments also rushed out," she said.
The quake comes two weeks after Japan was hit by one of the biggest earthquakes on record.
"Five monasteries and 35 buildings collapsed in the town. Those people were killed when the buildings collapsed," said the official, who declined to be named.
wenty people were injured in Tarlay in the district of Tachileik, and the official said the main road into the area was closed after being damaged.
Just across the border from Tachileik, Thai authorities said a 52-year-old woman was killed in Mae Sai district after a wall of her house collapsed.
Terrified residents across the region fled their homes, tall buildings swayed and hospitals and schools were evacuated during the tremors.
The quake struck 60 miles (90km) north of Chiang Rai and 235 kilometres (150 miles) north-northeast of Chiang Mai, Thailand's second city and a popular tourist destination.
Its epicentre was close to the borders with Thailand and Laos and was just six miles (10km) deep.
The shaking was also felt throughout China's southwest province of Yunnan, according to state-run China National Radio, but no casualties or structural collapses had been reported.
Some residents of the Vietnamese capital Hanoi also fled their homes in panic when the quake shook the city.
Nguyen Thi Hong Hanh, 36, who lives on the 10th floor of a highrise, said her husband noticed their pet fish shaking in their tank.
"We all rushed to the street. All the other people in the apartments also rushed out," she said.
The quake comes two weeks after Japan was hit by one of the biggest earthquakes on record.