Sanan Kamsridaeng, 65, confessed to raping the girl - who was aged under 15 at the time - last year and detaining her against her will when he was still a monk, a Bangkok criminal court official told AFP.
"He was sentenced on Thursday (June 26) to six years in jail for the first count... and five years for the second count. But because he confessed the judge cut his sentence to five years and six months," the official said.
He was disrobed after his arrest last year.
In recent weeks Thailand's national religion has faced damaging accusations linked to monks' behaviour, with high-profile scandals ranging from reports of monks taking drugs and drinking, to a case in May of five defrocked abbots charged with sexually abusing boys.
The National Office of Buddhism (NOB) has launched a hotline to report monks behaving badly, after the leader of Thailand's military junta expressed concern over the image of Buddhism.
The religion counts an estimated 95 percent of its 67 million population as devotees.
Napparat Benjawattananant, head of the office, said the hotline has received 142 complaints against unruly monks so far.
"But for sexual complaints we have to carry out in depth investigation," he said, adding monks found to have had sex should also face criminal charges. AFP