Porous media hydrodynamics are altered by the reduced gravitational force experienced in microgravity (e.g. aboard the International Space Station). Modeling the effects of reduced gravity on liquid absorption is critical to understanding and describing fluid-porous media wetting behavior in space. Parabolic flight aboard jet aircraft can provide approximately 20 seconds of weightlessness in which to perform experiments. The objectives of this study were to i) obtain measurements of liquid imbibition in microgravity (ug) and ii) to apply capillary-dominated imbibition models to characterize and describe this process. Liquid imbibition during ug was visually recorded in glass beads and baked ceramic aggregates ranging in size from 0.25 to 3.5 mm. The Philip infiltration equation was applied to model imbibition in these media and to compare the sorptivity parameter determined under earth's gravity using the same porous media. Capillary forces dominate in ug yielding ‘true' sorptivity, especially in coarse-textured porous media, which on earth, are dominated by gravitational force. Sorptivity values obtained in ug lie between those of horizontal and vertically upward oriented 1g imbibition measurements. Imbibition in pre-wet porous media exhibited a doubling of the sorptivity compared to the same dry media. As a special case, liquid withdrawal was also observed under microgravity and compared to 1g measurements. Normalized liquid withdrawal volumes in ug were 70% of 1g measurements in 3.5 mm beads, but both 1g and ug measurements were shown to converge to a normalized volume fraction of 0.33 in particles smaller than 0.5 mm in diameter.