This study is entitled Pronunciation Errors in Students? English-Speaking Performance. It aims at analyzing pronunciation errors found in students? speaking performance. Besides, this study also investigates the factors that cause pronunciation errors in student speaking performance. The data of this study were obtained from the results of a speaking test conducted on 8th Grader of Class C Students of SMP Negeri 2 Blahbatuh, Gianyar Regency, Bali, Indonesia. The test was done by asking students to briefly told their experiences during the holidays. The documentation method was used to obtain the data from oral material (speaking performance). A note-taking technique was applied to mark down the relevant data for the study. The data of the study were qualitatively analysed based on theory of phonological errors by Keshavarz (2012), and factors causing errors by Brown (2000). The analysis of this study was presented in informal methods. In the informal method, each problem in this study was presented narratively to make the analysis understood easily. The finding reveals that there are several errors found in students? speaking performance. Errors include pronunciation errors of English vowels, consonants, and diphthong. The cause of errors in pronunciation of English consonants and English vowels is the intralingual and interlingual factors. Pronunciation errors of English consonant are mostly caused by interlingual factors, while vowel pronunciation errors tend to be caused by intralingual factors.