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Cellulose nanocrystals (CNCs), usually considered as isotropically polar nanoparticles, are sheet-like crystalline assemblies of cellulose chains. Here, we link the anisotropy of the CNC structure to an amphiphilic behavior in suspension. The Hansen solubility parameters (HSP: δ D; δ P; δ H) of wood-based H 2 SO 4-hydrolyzed CNCs were measured from sedimentation tests in a wide set of 59 solvents and binary mixtures. Two sets of cohesion parameters corresponding to a polar surface (18.1; 20.4; 15.3)±(0.5; 0.5; 0.4) MPa 1/2 and to a mildly non-polar one (17.4; 4.8; 6.5)±(0.3; 0.5; 0.6) MPa 1/2 were determined, with respective solubility radii of 7.8 and 2.1 MPa 1/2. The polar sphere is thought to correspond to the (110) & (1 1¯ 0) surfaces of cellulose I β nanocrystals, while the smaller non-polar sphere is coherent with the exposure of (200) surfaces. The HSP graph provides new insights on the amphiphilic …