The wetting and absorption properties of internally sized paper sheets with differing alkyl ketene dimer (AKD) load were investigated using a numberof wetting and absorption tests, including dynamic contact-angle measurements and dynamic surface-penetration and edge-penetration measurements. Special attention was paid to the spontaneous spreading dynamics of water drops at the surface of the paper. Pure water and aqueous surfactant solutions were used as wetting liquids. The experiments were carried out at several different temperatures. It was shown that AKD-sized papers revealed a large wetting hysteresis indicative of nonuniform size distribution.Wettability of both sized and unsized paper increased with temperature, but the effect was significantly smaller than expected. At elevated temperatures, gas-phase vapour transport played a significant role in water pickup by paper. Surfactant-enhanced wetting and sizing loss are discussed. The experimental results obtained are scrutinized within a theoretical framework developed to model the absorbency of paper.