By focusing on 179 elementary school children, the present cross-sectional questionnaire study aimed to examine gender and immigrant-native differences in competence and affect self-concepts as well as academic achievement and the relations of those two self-concept components to academic achievement in the domains of mathematics and German. Results of analysis of variance showed that boys' competence self-concept in mathematics was more positive than that of girls, while girls' affect self-concept in German was more positive than that of boys. Immigrant children showed a higher affect self-concept in German than native-born peers. Boys' superior competence self-concept in mathematics was more pronounced for native-born children than immigrant peers, whereas immigrant girls' competence self-concept in mathematics was more pronounced than that of native-born girls. Competence self-concepts were more highly related to academic achievement than affect self-concepts.