This study investigates the interlaboratory comparability and reproducibility of all-solid-state battery (ASSB) cell cycling performance. Commercially sourced materials—LiNi0.6Mn0.2Co0.2O2 for the positive electrode, Li6PS5Cl as the solid electrolyte, and indium for the negative electrode—are provided to 21 research groups, who are asked to assemble and cycle ASSB cells using their own protocols but following a specific electrochemical protocol. The results show significant variability in assembly and electrochemical performance, including differences in processing pressures, pressing durations, and In-to-Li ratios. Despite this variability, an initial open circuit voltage (OCV) of 2.5 and 2.7 V vs Li+ is a good predictor of successful cycling for cells using these materials. The study recommends reporting all-solid-state battery cycling results in triplicate and suggests a set of parameters for reporting to improve comparability and validation of cell performance. The findings highlight the need for standardized testing and further work to enhance the comparability of ASSB data.This study investigates the interlaboratory comparability and reproducibility of all-solid-state battery (ASSB) cell cycling performance. Commercially sourced materials—LiNi0.6Mn0.2Co0.2O2 for the positive electrode, Li6PS5Cl as the solid electrolyte, and indium for the negative electrode—are provided to 21 research groups, who are asked to assemble and cycle ASSB cells using their own protocols but following a specific electrochemical protocol. The results show significant variability in assembly and electrochemical performance, including differences in processing pressures, pressing durations, and In-to-Li ratios. Despite this variability, an initial open circuit voltage (OCV) of 2.5 and 2.7 V vs Li+ is a good predictor of successful cycling for cells using these materials. The study recommends reporting all-solid-state battery cycling results in triplicate and suggests a set of parameters for reporting to improve comparability and validation of cell performance. The findings highlight the need for standardized testing and further work to enhance the comparability of ASSB data.