This study is an attempt to determine learners' attitudes and perceptions about critical thinking dispositions and their achievement levels in Business English classes. The participants (N=91, 61 males and 30 females) are second- and third-year undergraduate students from Management and Information Systems department enrolled in the Faculty of Economics and Administrative Sciences at a state university in Turkey, who have taken the Business English Course during the 2018-2019 academic year, fall term. The research was designed as a quantitative study. For the measurement of learners' tendency towards critical thinking dispositions, the California Critical Thinking Disposition Inventory (CCTDI), a survey instrument (51 questions, 6 subscales) adapted and translated into Turkish by Kökdemir (2003) was employed as a data collection tool. These subscales are about truth-seeking, openmindedness, analyticity, systematicity, critical thinking, self-confidence and inquisitiveness. At the end of the semester, for the English achievement level of learners, final exam results were taken into consideration and evaluated. The data collected were analyzed through SPSS 22.0. Findings indicate that the relationship between students' critical thinking dispositions (CTD hereafter) and the final scores are not statistically significant. Also, students' level of education does not affect the tendency of the participants in terms of CTD. However, it can be said that female students are more successful than male students in academic English course. Implications are included for critical thinking dispositions to enhance academic/business English language courses in Turkey.