This paper analyzes public sector efficiency across 23 industrialized OECD countries using a composite set of performance and efficiency indicators. It measures public sector performance (PSP) and efficiency (PSE) by considering both input and output factors. The study finds that countries with smaller public sectors generally report higher overall performance and efficiency, while larger public sectors tend to have more equal income distribution. The analysis uses a non-parametric production frontier technique called FDH to assess input and output efficiency. The results indicate that the average inefficiency in public sector spending is about 20%. Countries like Japan, Luxembourg, Australia, the United States, and Switzerland show the highest overall efficiency. The study also highlights that public sector efficiency varies significantly across countries, with some countries showing substantial improvements in performance over the last decade. However, the results should be interpreted with caution due to data comparability issues and the difficulty in isolating the effects of public spending on outcomes. The findings suggest that government size may be too large in many industrialized countries, with declining marginal products being prevalent. The paper concludes that public sector efficiency is an important factor in economic performance, and that further research is needed to understand the specific impacts of public spending on outcomes.This paper analyzes public sector efficiency across 23 industrialized OECD countries using a composite set of performance and efficiency indicators. It measures public sector performance (PSP) and efficiency (PSE) by considering both input and output factors. The study finds that countries with smaller public sectors generally report higher overall performance and efficiency, while larger public sectors tend to have more equal income distribution. The analysis uses a non-parametric production frontier technique called FDH to assess input and output efficiency. The results indicate that the average inefficiency in public sector spending is about 20%. Countries like Japan, Luxembourg, Australia, the United States, and Switzerland show the highest overall efficiency. The study also highlights that public sector efficiency varies significantly across countries, with some countries showing substantial improvements in performance over the last decade. However, the results should be interpreted with caution due to data comparability issues and the difficulty in isolating the effects of public spending on outcomes. The findings suggest that government size may be too large in many industrialized countries, with declining marginal products being prevalent. The paper concludes that public sector efficiency is an important factor in economic performance, and that further research is needed to understand the specific impacts of public spending on outcomes.