Private schools in Tapanuli Tengah Regency face significant challenges in maintaining operational sustainability, particularly after the flash floods and landslides of November 2025, which reduced tuition revenue, disrupted teaching and learning activities, and weakened public trust in schools. This study aims to examine the effect of budgetary participation and accounting information systems on school operational sustainability, and to examine the moderating role of financial resilience on both relationships. The study employs a quantitative, associative research design. The population consists of all private senior and vocational high schools in Tapanuli Tengah Regency, using census sampling that involved the principal, treasurer, and one teacher representative from each school as respondents. Data were collected through a Likert-scale questionnaire and analyzed using Structural Equation Modeling based on Partial Least Squares (SEM-PLS) with SmartPLS software. The results show that budgetary participation and accounting information systems have a positive and significant effect on school operational sustainability. Financial resilience was found to moderate and strengthen the effects of both variables, with a stronger moderating role in the relationship between accounting information systems and sustainability than in the relationship involving budgetary participation. These findings indicate that a school's financial resilience determines the extent to which these factors can support operational continuity, particularly in disaster-prone areas. This study contributes theoretically to management accounting and educational-sector accounting studies, and practically to schools and local government in formulating financial policies that support school operational sustainability after natural disasters.