OBJECTIVE To assess the short- and medium-term effects of the posture education program (PEP) for students of elementary school regarding theoretical knowledge and posture during activities of daily living (ADLs). METHODS The sample consisted of 38 students (aged 8-12 years) in the third grade of elementary school in Porto Alegre, Rio Grande do Sul (Southern Brazil). The children were evaluated in three moments: prior to attending the PEP (pretest); after attending the PEP (post-test); and five months after the conclusion of the PEP, immediately after a learning review of four lessons (five months follow-up). The posture during ADLs and the theoretical knowledge about spine and body posture were assessed, based on specific instruments (layout for assessing the dynamic posture - LADy; and questionnaire). The Friedman test, post hoc Wilcoxon test, and Bonferroni correction were applied to identify the differences among the evaluative moments, as they are statistically significant at α<0.05. RESULTS No statistically significant difference was found between the post-test and follow-up concerning the theoretical knowledge. In addition, no statistically significant difference was found between post-test and follow-up in relation to ADLs; however, the performance of students was higher in the post-test and follow-up, when compared with the pretest. CONCLUSIONS Immediately after the PEP's conclusion, the students improved their posture in ADLs. These positive effects and the theoretical knowledge were retained in the follow-up (after the review lessons).