Observed climate data used as input in glacier models are expected to differ among datasets, particularly those for precipitation at high elevations. Differences among datasets have not yet been described as a cause of uncertainty in projections of future changes in glacier mass, although uncertainty caused by varying future climate projections among general circulation models (GCMs) has often been discussed. Differences among climate datasets are expected to propagate as uncertainty in future changes in glacier mass due to bias correction of GCMs and calibration of glacier models. We project ensemble future changes in the mass of glaciers in Asia through the year 2100 using a glacier model. A set of 18 combinations of inputs, including two temperature datasets, three precipitation datasets, and future air temperature and precipitation projections from three GCMs were used. The uncertainty in projected changes in glacier mass was partitioned into three distinct sources: GCM uncertainty, observed air temperature uncertainty, and observed precipitation uncertainty. Our findings indicate that, in addition to the differences in climate projections among GCMs, differences among climate datasets can propagate uncertainty into projected changes in glacier mass. Significant differences in observed precipitation did not cause major uncertainty in projected changes in glacier mass.