In this study, it was aimed to determine ethical reasoning of lecturers in STEM disciplines in terms of several independent variables (gender, working another institution, age, academic title, academic discipline, service period). This study was designed as a survey research. Lecturers in STEM disciplines in Kahramanmaras Sutçuimam University were selected as participants of the study. ''Ethical Reasoning Instrument (ERI)" which was developed by Titus, Zoltowski, Huyck, and Oakes (2011) was used in order to collect data by adapting into Turkish. Data were analyzed by the help of independent sample t-test, one-way ANOVA and Kruskal-Wallis tests. The findings indicated that for all independent variables there were no statistically significant difference (p>0.05) in ethical reasoning of lecturers. As an interesting result, it was determined that lecturers in engineering discipline have less ethical awareness than lecturers in medicine and science disciplines.