The study investigated university lecturers' attitudes towards English medium instruction (EMI), reasons for EMI adoption, effects of EMI on official languages and lecturers' preference for language of instruction. It also examined the impact of gender, English proficiency, country and medium of instruction of lecturers' highest educational degree as well as their education level on their responses. A survey questionnaire was employed to collect data from 234 lecturers at four public universities based in the northeast of Afghanistan. The author used both descriptive and inferential statistics to analyse the data. The results showed that lecturers had strong positive attitudes towards EMI. They were in favour of EMI adoption at universities for various reasons, such as preparing students for national and international job markets. Although the lecturers were aware of the negative impacts of EMI on official languages and challenges against EMI implementation, the vast majority preferred EMI and bilingual education. The participants' English proficiency, country and medium of instruction in their highest educational degree as well as their educational level had a significant impact on their attitudes towards and preference for EMI.