Under the Immigration and Nationality Act (INA), lawful permanent residents are rendered removable if they commit an “aggravated felony” at any time after they are admitted into the United States. Significant interpretive issues arise in determining whether a non-citizen’s state-based criminal conviction meets the INA’s definition of an aggravated felony. One aggravated felony enumerated in the INA is “sexual abuse of a minor.” The Board of Immigration Appeals (BIA) has interpreted the phrase using a broad federal definition as a guide. In Estrada-Espinoza v. Mukasey, however, the Ninth Circuit declined to defer to the BIA’s interpretation because the BIA’s decision was not a precedential opinion warranting deference. In reviewing whether a California statutory rape conviction constituted sexual abuse of a minor, the Estrada-Espinoza court applied a different federal definition and concluded there was no violation, and thus, Mr. Estrada-Espinoza was not deportable. The question of how to define “sexual abuse of a minor” will likely come before the Ninth Circuit on substantive grounds once the BIA issues a deference-warranting definition of the provision. This Comment argues that when the Ninth Circuit revisits the issue, it should not defer to the BIA, regardless of the definition it promulgates. Rather, the court should rule that the phrase “sexual abuse of a minor” is unambiguous based on its plain meaning, the Ninth Circuit’s precedent, holdings from sister circuits, and policy considerations. This holding would be consistent with the best interpretation of the statute, and Chevron U.S.A. v. Natural Resources Defense Council and its progeny