I consider decision-making constrained by considerations of morality, rationality, or other virtues. The decision maker (DM) has a true preference over outcomes, but feels compelled to choose among outcomes that are top-ranked by some preference that he considers "justifiable." This model unites a broad class of empirical work on distributional preferences, charitable donations, prejudice/discrimination, and corruption/bribery. I provide a behavioral characterization of the model. I also show that the set of justifications can be identified from choice behavior when the true preference is known, and that choice behavior substantially restricts both the true preference and justifications when neither is known. I argue that the justifiability model represents an advancement over existing models of rationalization because the structure it places on possible "rationales" improves tractability, interpretation and identification.