Ethics in research is fundamental to ensuring scientific integrity, the protection of human and animal subjects, and the advancement of knowledge in a responsible manner. This chapter explores the principles and practical applications of ethical decision-making in research, with a focus on dental research. It discusses various ethical decision-making theories, the evolution of research ethics, and key ethical principles such as respect for persons, beneficence, nonmaleficence, justice, veracity, and informed consent including the vulnerable groups. The role of institutional review boards in safeguarding ethical research practices is also presented. Furthermore, special attention is given to ethical considerations in data management, artificial intelligence, big data, and collaborative research. Additionally, the chapter outlines ethical standards in animal research, highlighting the significance of the 3Rs principles: Replacement, Reduction, and Refinement. The discussion underscores the importance of balancing scientific progress with ethical responsibility, ensuring that research remains beneficial to both individuals and society while maintaining public trust.