This research conducted to explain English Pronunciation Problems of Thai students in Semarang. This research aimed to explain the factors of the problems that cause the difficulties of the English pronunciation of Thai students in Semarang and the implication of the dialects Thai students towards the English pronunciation of Thai students in Semarang. The researcher concluded this analysis to Thai students who have studied at the College in Semarang, then the researcher conducted 31 participants who are selected randomly from different Colleges as Thai students in Semarang. Furthermore, the data the researcher used descriptive qualitative analysis techniques which collected by observation, interview, and record. This research found that there are many factors of the problems that cause the problems of the English pronunciation for Thai students that are; 1) The student does not get enough to practice English pronunciation even though in/outside the classroom. 2) The teacher used the local language while teaching the English lesson. 3) The local language/Thai accent causes the problems of pronouncing English. 4) The teacher does not emphasize the students in pronounced English. 5) Some students feel uncomfortable and inattentive in learning English. 6) The student feels unmotivated in learning English. 7) Some students weren't interested the English, which makes them don't pay attention to it. Then, most of the implications that caused the problem of English pronunciation for Thai students are because English is a foreign language in Thailand, so the local language would be the first obstacle for the implementation of the English Learning between teachers and students. Therefore it is very usual if some learners are not interested in English lessons especially in their English performance because they face difficulties in pronouncing and lack of motivation and confidence. The findings are interpreted to have pedagogical implications for EFL teachers in general and in Thais’ communities, in particular.