Background Ethics positions, consisting of the two fundamental dimensions of idealism and relativism, influence individuals’ decision-making significantly. Particularly in an applied field such as nursing, the ethics positions of nurses can play a significant role in clinical decisions. Therefore, it is important to know the factors affecting the ethics positions of nurses in clinical decision-making. Aim The aim of the study is to examine the factors affecting the ethics positions of nursing students in clinical decision-making. Research design This is a two-phase sequential explanatory mixed methods study designed in accordance with the COREQ criteria. A participant Information Form and the Ethics Position Questionnaire were used to collect quantitative data. Qualitative data were obtained through focus group interviews. Ethical considerations This study was conducted after receiving written permission from X University Ethics Board. Additionally, permission was obtained from the participating nursing faculty. Participants Among the fourth-year nursing students, 180 students participated in the quantitative phase and 30 students in the qualitative phase of the study. Results The quantitative data analysis showed that the idealism sub-dimension mean scores of the participants were higher than the relativism sub-dimension mean scores. The analysis of the qualitative data resulted in four main themes that influence participants’ ethics positions in clinical decision-making: (1) attitudes of role models in clinical practice (staff nurses/mentors/lecturers), (2) resources related to clinical practice (labs, hospitals/classrooms), (3) health system (hospital policies/school policies), and (4) personal differences (act with emotion/act with logic). Conclusion The results showed that the health system, role models in the clinic, personal differences, and skill-related resources affect the ethics positions of nursing students in clinical decision-making. In this regard, awareness can be raised by providing training to nursing students by academic instructors on ethics positions and the factors that are determined to affect ethics positions in clinical decision-making.