This study investigated the measurement invariance of school and teacher Information, Communication and Technology (ICT) readiness among 57 countries that participated in the Program in International Student Assessment (PISA) 2018 assessment. School and teacher ICT readiness scale is 11-item scale with two subfactors: school ICT readiness and teacher ICT readiness subscales (Bozkus, "International Online Journal of Education and Teaching," 8(3), 1560-1579, 2021). With the novel alignment optimization method, we revealed that the school ICT readiness subscale was invariant for unbiased country comparisons but overall noninvariance was identified for the teacher ICT readiness subscale. Additionally, the rank of the school ICT readiness factor means indicated that Singapore, Sweden, B-S-J-Z (regions of China), United Arab Emirates and United States were among the top league, while countries like Indonesia, Poland, Ireland in between, and Japan, Mexico, Colombia, Argentina and Brazil ranked comparatively the lowest. Measures of school location, school type and class size further confirmed the validity of the school ICT readiness subscale. It was expected that the study would enhance our understanding of school and teacher ICT readiness across countries with the application of an alternative alignment optimization approach in examining ICT related scales.