The Levels of Emotional Awareness Scale for Children (LEAS-C) is a scenario-based assessment of the ability to identify and describe the emotions of self and others. The present study is aimed at developing the Japanese version of the LEAS-C (J-LEAS-C) and examining its reliability and validity. The translated version of the LEAS-C and the measures of empathy and alexithymic tendencies were administered to 299 junior high school students. The J-LEAS-C showed sufficient inter-rater reliability and high internal consistency among the scenarios. A confirmatory factor analysis revealed the acceptable fit indices of the theoretically-expected one-factor model. As expected, emotional awareness was positively associated with two dimensions of empathy: “empathetic concern” and “cognitive empathy,” and showed a weak negative correlation with one of the factors of the alexithymic tendencies: “externally-oriented thinking.” Finally, the J-LEAS-C scores showed a gender difference consistent with previous studies in which girls scored higher than boys. Although the practical usefulness and cultural aspects that may influence the scores remain an issue, these findings support the reliability and validity of the J-LEAS-C.