The effect of voids on moisture absorption of T300/914 laminates was discussed in this paper. The experimental results revealed that the moisture content increases with the immersion time at first and then reach a pseudo equilibrium state for the compressive and bending specimens. The saturated moisture content and the rate of water uptake increased with porosity increasing from 0.71% to 1.50%, which proved voids accelerate moisture absorption. The geometry of the specimens influences the moisture behavior. The saturated moisture content increased with the decreasing width of the specimens. The most significant increase in dimensional change is in the thickness and length direction, followed by the width direction.