In the IEA PIRLS International Report, a number of indices of reading-related constructs were introduced for the purpose of explaining the variation in reading achievement. These indices, however, raise issues of reliability and validity, due to the way in which they are derived and due to the quality of the data. Targeting these issues, the current study investigates the measurement properties of some of these reading-related factors by a multivariate latent variable modeling approach. The data is drawn from the PIRLS questionnaires of the fourth graders in six countries. On the basis of a series of confirmatory factor analytic models individual factor scores of these constructs are estimated. The results indicate that the most significant advantage of the suggested approach is that it makes efficient use of the available data to estimate factor scores with higher reliability and validity than the observed index scores.