Aim: The objective of this paper is to examine the level of psychiatric symptoms and associated factors among Thai migrants from the southernmost Thai provinces of Pattani, Yala, and Narithiwat who are working in Malaysia. Comparisons will be made with the sending population in the southernmost provinces of Thailand. Methods: Data are drawn from survey and in-depth interviews with Thai migrants who are working in Malaysia. Comparisons are made with a probability sample of working age adults in Thailand. The twenty item Self Reporting Questionnaire (SRQ) was the measure of mental health. Results: The study found that the migrants, on average, have normal levels of psychiatric symptoms. However, although about 24% of migrants reported more eight or more symptoms that may indicate a need for evaluation. There are many stressors in their lives including distance from families, reduced social support, legal matters surrounding immigration, and discrimination/exploitation of migrant groups. Conclusion: The study highlights the need for policy makers and non-governmental organizations to give attention to migrants’ mental health, well-being and sustainable livelihoods.