RESUMEN
This study adapted and examined the psychometric properties of the Youth Life Orientation Test (YLOT)-a measure to evaluate dispositional optimism and pessimism-in a Brazilian sample of children and adolescents aged between 5 and 16 years. The factor structure, reliability, convergent validity, and invariance of the YLOT were evaluated within and across four age groups (N1 = 266, N2 = 246, N3 = 211, and N4 = 253). Participants were 976 students (51.9% girls) who answered the YLOT and subjective well-being measures and 350 parents (51.6% female) who answered a parent-report measure of optimism. Confirmatory factor analyses suggested an oblique two-factor model best fit the data, indicating that optimism and pessimism are independent factors. These factors demonstrated adequate reliability and convergent validity evidence with well-being measures. Additionally, scalar invariance was obtained, and latent mean analyses indicated optimism decreases and pessimism increases in participants from 5 to 13 years old. These results support the use of YLOT in Brazil. (PsycInfo Database Record (c) 2022 APA, all rights reserved).