This study investigated the enjoyment, boredom, and anxiety of elementary school students and the relations of these emotions with achievement in two domains. Seven-hundred-and-sixty-seven second- and fourth-graders completed an adaptation of the Achievement Emotions Questionnaire-Elementary School (AEQ-ES: Lichtenfeld, Pekrun, Stupnisky, Reiss, & Murayama, 2012) assessing their emotions in their native language and mathematics. The hierarchical model of the instrument was invariant across countries (Italy, Germany, United States), grades, gender, and domains. Anxiety related negatively to achievement, while enjoyment related positively to achievement only in mathematics. Second-graders reported more enjoyment and less boredom and anxiety than fourth-graders. Overall, mathematics resulted in better emotions than native language. The results have implications for future research on achievement emotions in elementary school.