CONCLUSION The results of this study have several pedagogical implications. Developing students’ oral presentation competence has been considered of importance as it contributes to the knowledge, skills, and attitudes in informing, self-expressing, or persuading the audience. Oral presentation skill is not only included in the 21st-century skills, but also it is a required skill when students enter the workplace. In this instance, the presentation course should be designed in a way that can assist students in acquiring specific linguistic features, ranging from vocabulary, pronunciation, and grammar, that are essential for a successful presentation. Teacher feedback should be directed upon the construction of such knowledge, not merely on error correction. In the context of the B1 learners, they are shy and feel anxious when they attempt to speak English with others, especially foreigners. Thai students prefer to remain silent as they are afraid of making mistakes, mispronounce the words and/or laughed at by their friends. All these challenges, involving anxiety, fear of making mistakes, passivity, shyness, and lack of confidence, should be considered in teacher feedback.17 When students receive positive and constructive feedback, they will likely build self-confidence, which will consequently improve their English proficiency as well as speaking skills that will be perceptible in their presentation task. Nonetheless, there are limitations to be acknowledged. This study relied primarily on students’ scores and survey questionnaire data. It is believed that the addition of qualitative data would have offered more insights into the results. Although this study integrated model presentation videos into the course design, a specific analysis was not conducted on this particular treatment. It is assumed that students’ backgrounds, other than their fields of study, may have a role, yet they are not part of the variables of interest in this study. Thus, it is recommended that future studies use a mixed-methods approach that includes other educational backgrounds in the analysis. To sum up, the findings of this quantitative research indicate the importance of English proficiency over self confidence and teacher feedback on developing students’ English oral presentation skills. Within self confidence, two underlying factors are suggested, while teacher feedback is unidimensional. It is important to underline that the majority of the students involved in this study are at a low level of proficiency, which may have lead to self-confidence and teacher feedback not having significant effects as expected. More investigation to further explore this assumption is needed. 18 The last finding pointed out that English proficiency was the only significant predictor for students’ final English oral presentation, while self-confidence and teacher feedback were not. This finding was consistent in all students in both the Sciences and Technology, and Humanities and Social Science fields. Previous related studies have only examined how oral presentation could enhance proficiency. Hence, this finding sheds light on the direct effect of English proficiency on students’ English presentation performance. Nevertheless, this finding does not support studies suggesting predictive roles of self-confidence and teacher feedback on students’ oral presentation performance. In a comparative study between teacher and peer feedback, Murillo-Zamorano and Montanero found that teacher feedback could only improve students’ performance by 5%, half of peer feedback’s contribution. Moreover, the present study also performed mediation analyses to find whether English proficiency could be the mediator for self-confidence and teacher feedback to students’ presentation performance. The results did not reveal any potential mediators. The mediation results strengthen the indication that only English proficiency could explain students’ outcomes in an oral presentation. Finally, for the question, "Do self-confidence, teacher feedback, and English proficiency matter in developing students’ English oral presentation competence?", this study confirms that English proficiency is the most important element in developing oral presentation competence. It can be that higher proficiency students will likely present better and/or oral presentation can be integrated into class activity as a means to enhance proficiency. Moreover, having confidence and teacher feedback in a presentation course does not necessarily result in improvement in students’ presentation performance. It is suspected that self-confidence and teacher feedback may be attached to specific circumstances of contextual practice, including the types of feedback given to students. For instance, underline that teacher feedback should highlight the acquisition of communicative and oral presentation competence, in which error correction is not the primary objective. Additionally, even though significant differences across academic fields are not identified, the various results from the examinations of the three types of data in this study should express the effects of educational backgrounds and sample size.19