Understanding attitudes toward science and measuring them remain two major challenges for science teaching. This article reviews the concept of attitudes toward science and their measurement. It subsequently analyzes the psychometric properties of the "Test of Science-Related Attitudes" (TOSRA), such as its construct validity, its discriminant and concurrent validity, and its reliability. The evidence presented suggests that TOSRA, in its Spanish-adapted version, has adequate construct validity regarding its theoretical referents, as well as good indexes of reliability. In addition, it determines the attitudes toward science of secondary school students in Santiago de Chile (n = 664) and analyzes the sex variable as a differentiating factor in such attitudes. The analysis by sex revealed low-relevance gender difference. The results are contrasted with those obtained in English-speaking countries. This TOSRA sample showed good psychometric parameters for measuring and evaluating attitudes toward science, which can be used in classrooms of Spanish-speaking countries or with immigrant populations with limited English proficiency. (A test is appended in Spanish.)