Critical research in information systems is based on and inspired by ethics and morality. In order to support this proposition, this paper will suggest a way of classifying critical research that differs from definitions common IS research. According to the current definition, research is critical when it is motivated by the intention to change social realities and promote emancipation. Based on this critical intention, critical research is furthermore characterized by critical topics, critical theories, and critical methodologies. Using these criteria of critical research, the paper argues that critical research is ethical in nature. To support this view, the paper introduces the concepts of ethics and morality by analysing two traditions of moral philosophy, here called the 'German tradition' and the 'French tradition'. Using three examples of current critical research in information systems, the paper will show that ethics and morality strongly influence critical intention, topics and theories. Having thus established the ethical nature of critical research, the paper concludes by discussing the weaknesses of critical research from the point of view of ethics and morality.