Soil wettability is a dynamic soil property, which results from complex interactions between many other physical and chemical properties. As opposed to water repellency, soil wettability defines the ability of the soil to intake water. The term hydrophilicity (antonym of hydrophobicity) strictly refers to the molecular origin of soil surface-water interactions determined by the physiochemical nature of the structure of soil surfaces. Wettability can be measured as a wetting rate, which is affected by the organic and mineral composition of the soil surfaces (hydrophilic and/or hydrophobic) and by the structural arrangement of soil components (solids, water solution, and air) at larger scale. At a molecular scale the composition of solid surface-exposed chemical groups (hydrophilic and/or hydrophobic) and their packing density determine wettability. At a scale ranging from soil aggregates to pedons to fields and larger soil units the spatial distribution and composition of soil particles and pores determine wettability. The pattern of wettability at different depths in the profile and at different landscape positions on the land surface determines the differences in wettability of fields, landscapes and regions. Soil porosity and soil pore characteristics determine wettability both by contributing to the water potential gradient and by determining the hydraulic conductivity. Water tension determines the hydraulic gradient, which controls the forces acting on the pore walls during wetting and may drastically change the porosity and dismantle the aggregate structure. Soil management practices affect soil pores directly through traffic and tillage, and indirectly through addition and removal of soil organic C. A clear relationship between organic C and wettability becomes evident when organic C is the dominant difference between soils while other properties such as clay content are similar. Soil organic C is one of the most effective tools for managing wettability. Soil organic C amount, quality and location within the soil structure are key factors of aggregate stability and aggregate wettability. Wettability is a desirable property for agricultural soils when it is related to stable porosity, as may be found in high organic matter soils (e.g., grasslands). Wettability is excessive when fast aggregate wetting results in aggregate destruction as observed in low organic matter cultivated soils. Wettability is too low when organic matter coatings on soil minerals make soil surfaces hydrophobic precluding soil water entry. Deposition of volatilized compounds after fire, patches of oil spills, thick layers of partially decomposed litter deposits and areas where dominant fungal growth produces high concentration of hydrophobic organic compounds are cases where increasing organic C decreases soil wettability. However in most agricultural soils, increased amounts of organic C tends to increase soil wettability, except when the location of the organic soil constituents prevents structural failure and soil dispersion during rapid wetting at low water tension. Different wettabilities result from differences in structural stability (pore stability) during wetting, while structural stability changes with wettability (rate of wetting). Therefore measurements of structural stability such as wet aggregate stability tests are a partial characterization of soil wetting behavior. Wet aggregate stability determined by directly wet-sieving air dry soil without any prewetting treatment subjects aggregates to sudden wetting at 0 water tension. Additional stress on aggregates are created by the scouring action of turbulent water and by the abrasion of aggregates during shaking. Other methods for measuring may add stress on the aggregate by the beating action of simulated raindrops but a major part of the measurement is a wettability measurement. A complex of soil properties contributes to wettability so that there is a lack of a unique simple relationship. Therefore, wettability measurements by simple tests (such as the water drop penetration time (WDPT) or the wetting rate under tension by the Büchner funnel apparatus) can integrate information on soil quality and support land management choices.