Objective: Examine acculturation and gender on intention to eat a healthful diet among Latino adolescents using the Theory of Planned Behavior. Design: Secondary analysis of data set and condensed version of the Short Acculturation Scale for Hispanics (SASH). Setting: Data collected from 34 randomly selected high schools in San Bernardino, CA. Participants: 265 Latino high school adolescents. Main Outcome Measures: Effects of acculturation and gender on variables of the Theory of Planned Behavior on intention to eat a healthful diet. Analysis: Multiple regression analysis examined acculturation/gender differences, and modifications on the prediction of intention. General linear modeling determined differences across gender and acculturation groups. Results: Females had stronger intention, more positive attitude, and greater subjective normative influence. Females indicated feeling healthy and looking good and males indicated good athletic performance as contributors to eating healthfully. Mother was influential for both genders, and stronger for females. Siblings were influential for less acculturated males, and friends were influential for highly acculturated females. Less acculturated adolescents had stronger intention to eat healthfully, more tolerance to give up liked food items, and more support and encouragement. Conclusions and Implications: Professionals need to take into account gender and acculturation differences when making dietary recommendations for Latino adolescents. (Contains 4 tables and 1 figure.)