Cultivating responsible future citizens is of increasing importance in school education. The objective of this study is to identify the most prominent factors from the school needs-based support that enhance early adolescents' sense of responsibility, using Self-Determination Theory as the framework. A questionnaire survey was conducted with 3034 10-year-old Finnish students (from 513 classes, with 50.4% female) and their teachers from the OECD Survey on Social and Emotional Skills. Hierarchical linear modelling was adopted, revealing the following key results: (1) contrary to the expectation, competence evaluation and relatedness support exhibited strong effects on adolescents' sense of responsibility, whereas the effect of autonomy support was indirect; (2) regarding competence evaluation, mastery evaluation emerged as the most effective strategy, whereas ability differentiation in tasks had the most adverse effect; (3) sense of school belonging emerged as a more beneficial form of relatedness support compared with perceived teachers' emotional support and (4) guided inquiry showed indirect associations through its effects on mastery evaluation and two types of relatedness support. Findings imply the most effective needs-based supports and related teaching practices to nurture adolescents' sense of responsibility.