The purpose of this study was to examine the dimensional structure and measurement invariance of Bryant’s Index of Empathy for Children and Adolescents (IECA) (Bryant, 1982) across gender in a representative sample of primary school-aged children in Spain. The sample consisted of 2,050 children (50.80% girls), with a mean age of 9.80 years (SD = 1.24), recruited from 27 primary schools. Exploratory and confirmatory factor analyses were conducted. The model that presented the best fit indices was Lasa, Holgado, Carrasco, and del Barrio’s (2008) three-factor model: Understanding Feelings, Feelings of Sadness, and Tearful Reaction. The levels of internal consistency for the subscales ranged from .76 to .83. In addition, the results partially support the measurement invariance of the IECA across gender. When the latent means of the empathy dimensions were compared across gender, statistically significant differences were found. These results coincide with those found in the literature showing the multidimensionality of the IECA. Specifically, the findings support its three-factor structure and its invariance across gender, making it a very useful instrument for exploring the expression of empathy in primary school children.