Objectives: The objective of the research is to assess the technical efficiency of national health systems in OECD member countries and to provide ideas to improve the efficiency of health systems in countries that have been identified as having a lower degree of efficiency as a result of the findings. Methods: The technical efficiency scores were calculated using one of the data envelopment analyses (DEA), the Weighted Slack-Based Measure (W-SBM). The Analytic Hierarchy Process was used to establish the aforementioned weights (AHP). Weights are calculated separately for both input and output variables. Results: The technical efficiency of the relevant countries' health systems is around 0.79, according to the data, and just 13 (36.1%) of the 36 countries have a fairly efficient health system. Conclusions: The outcomes of the study were supposed to aid health policymakers and management in improving system efficiency. In addition, since the number of studies examining the health systems of OECD countries with the W-SBM method is limited, it is thought that this study will make an important contribution to the literature.