Abstract: Much legal advice is provided after individuals have committed acts -- when they come before a tribunal -- rather than at the time they decide how to act. This paper considers the effects and social desirability of such legal advice. It is emphasized that legal advice tends to reduce expected sanctions, which may encourage acts subject to sanctions. There is, however, no a priort basis for believing that this is socially undesirable, because, among other reasons, it may be possible to raise the level of sanctions to offset their dilution due to legal advice. In addition, legal advice has no general tendency to improve the effectiveness of the legal system through its influence on the information presented to tribunals.