Criticality safety and reactor physics benchmark experiments may share certain components of the configurations and the same experimental techniques. This results in correlations between pairs of benchmark experiments. The correlations may impact validation results of criticality safety or reactor physics calculations as well as nuclear data validation. This paper presents how experimental correlations have been established for some fast and thermal neutron spectra configurations, documented in International Handbook of Evaluated Criticality Safety Benchmark Experiments and in International Handbook of Evaluated Reactor Physics Benchmark Experiments. It also discusses the impact of those correlations on validation of the most recent nuclear data libraries.