The purpose of this study is to develop a tool that can measure the educational well-being of elementary school students and to analyze the fit of the developed instrument. The measurement tool was based on four levels which include: (1) parents’ support, (2) teachers’ care, (3) students’ care in school, and (4) peer cooperation. It also had eight facets which include: (1) basic need, (2) family companionship, (3) happy learning, (4) teacher-student interaction, (5) safety protection, (6) school rules, (7) peer learning, and (8) peer interaction. The participants of this study were grades 5 and 6 students in Taiwan. Pre-testing with 197 grade 6 students was done to assess the validity and reliability of the developed scale. For the formal study, a total of 960 grade 6 students and 834 grades 5 and 6 students were recruited to join. The data collected underwent item analysis, reliability estimation, and confirmatory factor analysis. The results of the analyses were as follows: (1) the confirmatory factor analysis supported the four latent factors of the educational well-being scale; (2) the Cronbach’s alpha ranged from 0.73 to 0.89 for the elementary school students; (3) the cross-validation analysis with split-half samples implies that the study had a well-constructed stability model and that the scale had construct validity; and (4) the average scores of grade 5 students on the 8 facets and their overall score on educational well-being were all significantly higher than that of grade 6 students. Finally, several suggestions were proposed for future studies based on the results obtained.