Ethics based on subjectivity and freedom is little recognized as a plausible ground for informing the ethical practice of architectural design. Sartre’s existentialism is suited to address the ethical issue of architectural design freedom and subjectivity, and, as such, to contribute to an ethical framework for architectural design practice. Sartre’s philosophy is concerned with subjectivity and freedom and focuses on making choices in full awareness and acceptance of personal freedom and responsibility. Drawing on Sartrean concepts, an ethical framework for architectural design practice is proposed. It takes the form of a reflective process aiming at encouraging a clearer awareness of individual design freedom and responsibility that can lead to “authentic” architectural design practice. In this lies the value and significance of the framework for architectural design practice with regard to ethical design dilemmas.