This article considers the value of adopting a code of professional ethics for teachers. After having underlined how a code of ethics stands to benefits a community of educators--namely, by providing a mechanism for regulating autonomy and promoting a shared professional ethic--the article examines the principal arguments against codes of ethics. Three arguments are presented and analyzed in light of the codes of teacher ethics in place elsewhere in Canada. We conclude that a code of ethics must meet three conditions in order for it to be favorable to autonomous judgment rather than blind adhesion to pre-established norms: openness of meaning, space for dissidence, and avoidance of moralistic language.