This research aimed at investigating the anxiety levels affecting the English speaking ability of university students at a public university in the northeast region of Thailand as well as exploring the factors influencing such anxiety levels. The researchers employed a purposive sampling technique for the data collection by distributing 102 questionnaires to Thai first-year students who are studying in the English and Communication major at a public university in the northeast region of Thailand. The questionnaires were based on the anxiety evaluation models of Aida (1994), Horwitz et al. (1986), and Liu and Jackson (2008). Likert's scale was used to measure the levels of anxiety and the results revealed high levels of anxiety among the students with a mean of 3.50. Furthermore, the main component of anxiety was related to the students' beliefs about language learning followed by test anxiety. Moreover, the most significant factor affecting their speaking anxiety was grammar (72.55%), followed by vocabulary (53.94%) and English oral proficiency (53.92%), respectively.