Üstün, Ulaş2023-02-162023-02-162023Üstün, U. (2023). How well does self-concept predict science achievement across cultures? The mediating effect of autonomous motivation. International Journal of Science Education, 1–30.https://doi.org/10.1080/09500693.2023.2167244https://hdl.handle.net/11494/4703This study examines the direct and indirect relationships betweenkey motivational constructs and science achievement using TIMSS2019 data sets for Japan, Norway, and the United States. Thesample of the study includes 4,446 and 8,698 eighth graders inJapan and the United States, with 4,575 ninth graders in Norway.The structural equation model was built on the self-determination theory (SDT) and the self-enhancement model ofself-concept. The study’sfindings show that self-concept isconsistently the strongest predictor of science achievementamong motivational constructs for all three countries. In addition,the significant relationship between self-concept andautonomous motivation supports the SDT’s claims about basicpsychological needs. Although this relationship is consistent, asSDT predicts, across three countries, the magnitude of therelationship seems to be culture-dependent. Thefindings of thisstudy are discussed using the SDT and self-concept theory from acultural standpoint.eninfo:eu-repo/semantics/closedAccessSelf-determination theorySelf-concept; motivationScience achievementArticle10.1080/09500693.2023.2167244Q1Q1