A US embassy spokesman in Bangkok said the immigration and naturalisation service would be sending a team to interview Johnny and Luther Htoo next week.
"I can't say how long it will take before they are given permission to leave for the US," he said, but added that the interview was one of the final stages before permission to settle in the US was given.
The boy soldiers - believed to be in their early teens now - led the God's Army ethnic Karen guerrilla group for several years. They fought against the Burmese army with scores of followers who believed they had mystical powers.
They and 12 others surrendered to the Thai authorities in January, after border patrols cut off their food supply lines.
The twins, who were made famous around the world by pictures showing them carrying assault rifles and smoking cigars, told a news conference at the time that their fighting days were over.
They are living with their mother, sister and the 12 other former fighters in a Thai border patrol police camp 60 miles south-west of Bangkok.
The provincial governor said that the Thai national security council and the United Nations' refugees agency had set a schedule for them to leave.
"According to our policy, we plan to send them to a third country by the end of this year, but the final schedule and destination depend on the UNHCR [United Nations high commissioner for refugees]," he said.
He added that it was likely that they would go to the US, as they had been interviewed several times by US officials.
