This study investigates how institutional indiscipline affects sustainable economic and financial development in public and private sectors. Indiscipline manifests as corruption, absenteeism, embezzlement, and non-compliance with operational guidelines. Using a mixed-methods research design, data was gathered from 400 structural questionnaires administered to employees across selected public ministries and private firms. Hypotheses were tested using Multiple Linear Regression and Chi-square analysis. The findings reveal that indiscipline significantly cripples organizational productivity, deters foreign direct investment, and causes massive financial leakages. Public sector indiscipline primarily causes infrastructural decay and resource misallocation, while private sector indiscipline compromises market integrity and consumer trust. Consequently, the study concludes that robust corporate governance and strict statutory enforcement are non-negotiable for macroeconomic stability.