We report the structural properties and humidity sensing abilities of polypyrrole (PPy) composites containing ZnO nanoparticles (NPs) and Li2O. The PPy was synthesized following chemical oxidation method. The PPy50-ZnO(NPs) 50- Li2O x (where x = 0,2,4,6,8 & 10) composites were prepared by physical mixing using ball-milling method. The as-prepared composites were subjected to XRD, FTIR and EDAX. The structural analysis using these tools hinted at the presence of Li2O in the composites and the effect of variation of Li2O in the composites is emphasized. The humidity sensing ability of pristine PPy and the composites has been investigated, at room temperature, by measuring the change in electrical resistance of the sample due to the variation in relative humidity from 11–97% RH. The response to humidity and recovery times were determined. The mechanism of humidity sensing in these composites was understood by Grotthus theory. Among all the composites, the composite x = 10 (PZL10) has exhibited very good response and recovery time and has the potential to be used as a low-cost and highly effective humidity sensor.