A research on 126 students from Department of Biology, Ho Chi Minh City University of Education on the advantages and disadvantages of learning English with native and non-native English-speaking teachers was carried out in January, 2018. Data on their perceptions towards the reasons why they liked studying with teachers were gained from questionnaires. Thirty students in this research were also randomly selected for interview to get their suggestions for the better ways of teaching English. The result showed that biological students preferred learning pronunciation (88.1%), listening (64.2%), speaking (59.5%) and reading (57.9%) with native English-speaking teachers. However, most of them indicated preference to study grammar (63.5%) and writing (43.7%) with non-native English-speaking teachers. Students also suggested some effective ways of teaching English including choosing practical and interesting topics, applying good method of teaching, increasing time of teaching, transferring lesson by using games, stories,picnics, and so on. The findings will help Deans take into consideration the importance of teachers in teaching English.