Law n° 11.340/2006 emerged as an instrument for the prevention and repression of violence against women based on their gender. However, there are judicial positions and legislative debates about the purpose of the term inserted in the legislation, being questioned about which women the law refers to. For this reason, it is important to analyze the concepts of sex and gender, based on feminist theory, in addition to the brief presentation of a Bill that intends to define the gender's concept, as well as the recent decision of the Superior Court of Justice, which, in turn, was in favor of applying the Law to trans women. Therefore, this work intends, based on a bibliographic review, to identify theoretical references for classifying concepts and categories that explain the (in)adequacy of the Law in cases of violence against trans women. Is it a misinterpretation or is the Law actually insufficient to protect these women? [ABSTRACT FROM AUTHOR]