Theoretically, beliefs about English language learning have a psychological factor, such as predicting the rate of success or failure among learners in the classroom context. However, learners with different levels of language proficiency may perceive such beliefs in a different way, which may lead to the development of special needs, in terms of emphasizing their sustainable language development. The present study aims a) to investigate self-reported beliefs about English language learning among both low and high proficiency Thai students in university-level Foundation English courses, b) to identify the most prevalent affirmative beliefs among both student groups, and c) to identify the similarities and differences in their beliefs. The findings revealed that for low-proficiency students, vocabulary was an essential aspect of English language learning, while for high-proficiency students, regular practice was the key to their success. They also believed that anybody could speak English, when given the opportunity to practice speaking. The most prevalent affirmative beliefs among both sets of students were a) that anybody can speak English if given the opportunity and the time to practice, b) studying in a country where English is spoken as a native language will increase their language proficiency, and c) they want access to information resources in English. There were ten major differences between their beliefs (i.e. to learn English well, one must know at least one other foreign language, and be good at mathematics and sciences). Such findings would be a valuable resource to assist in the redesigning of English language courses, especially general English at the tertiary level, for learners with different levels of language proficiency.