This paper takes its point of departure in an article by Stevens [Stevens, B.: 1994, Journal of Business Ethics 54, 163–171], in which she identified a lack of knowledge regarding how corporate codes of ethics are communicated and affect behavior in organizations. Taking heed of this suggested gap, we review studies on corporate codes of ethics with an empirical content, published since 1994. The conclusion of the review is that we still lack knowledge on how codes work, how they are communicated and how they are transformed inside organizations. Stevens’ plea could even be extended, arguing that the knowledge gap might be of even more significance than in the mid-1990s. Some directions for how this situation can be approached in future studies are outlined in the paper.