This study investigated children's reasoning about laws and legal compliance. A total of 72 children, 24 each at 6, 8, and 10 years of age, made judgments of law evaluation (“Is it a good or bad law?”), legitimacy of legal regulation (“Is it OK or not for government to make a law?”), and law violation (“Is it OK or not for people to break the law?”) for three socially beneficial laws (a traffic law, a vaccination law, and a law requiring compulsory education for children under 16) and three unjust laws (denial of education to a class of persons, denial of medical care to the poor, and age discrimination). Participants also evaluated the application of laws in conflict scenarios in which a socially beneficial law infringed on individual freedom. Results showed that children considered a number of factors in their judgments, including the perceived justice of the law, its socially beneficial purpose, and its potential for infringement on individual freedoms and rights. The findings showed that children apply moral concepts of harm, rights, and justice to evaluate laws and to inform their judgments of legal compliance.