The research compiled important issues from evident data in the contexts of prostitution of hilltribe women in Chiang Mai, Chiang Rai, Phayao, and Mae Hong Son Provinces. The main factor bringing about the prostitution phenomenon among hilltribe women was the socio-economic factors which created pressure on the livelihoods of these women. The factors included social control mechanisms and cultural conditions that harbored positive attitude toward sexual relationships. The external social factor was composed of the ability to gain access to positive and negative information about prostitution where these women responded to by making it an alternative way to earn money.