<![CDATA[Sustainability maturity models developed for large corporations have limited applicability to Micro, Small, and Medium Enterprises due to implicit indicators and contextual misalignment. This conceptual study developed a Business Sustainability Maturity Model for Indonesian MSMEs through five prototyping stages: literature selection, narrative analysis, accounting overlay mapping, disclosure standard alignment, and digital deployment. The resulting model comprises nine value activities and 26 indicators, each described across five maturity levels, with 10 indicators supplemented by SAK EMKM-based accounting practices and 5 indicators aligned with the national sustainability disclosure standard PSPK-1. A 39-item self-assessment questionnaire was embedded into a web platform delivering instant maturity scores, visualisations, and improvement recommendations. Expert judgment involving 21 specialists, pilot testing with 255 MSME respondents across ten Indonesian provinces, and system testing collectively indicated that the model is relevant, feasible, and usable; detailed validation results are reported in a companion paper. The novelty lies in simultaneously integrating accounting-based measurement, disclosure-standard alignment, and digital operationalisation into a single MSME-oriented sustainability maturity instrument. Theoretically, the study advances maturity model literature by grounding progression levels in Stakeholder Theory, reframing sustainability maturity as the progressive broadening of stakeholder accountability. Practically, the model supports MSME operators, regulators, and supply-chain partners through standardised assessment.]]>
