The crystal structures of three salicyaldoxime compounds, namely 2-hy-droxy-4-methyl-benzaldehyde oxime, C H NO , , 2,4-di-hydroxy-benzaldehyde oxime, C H NO , , and 2-hy-droxy-4-meth-oxy-benzaldehyde oxime, C H NO , , are discussed. In each compound, the hydroxyl groups are essentially coplanar with their attached phenyl group. The inter-planar angles between the C=N-O moieties of the oxime unit and their attached phenyl rings are 0.08 (9), 1.08 (15) and 6.65 (15)° in , and , respectively. In all three mol-ecules, the 2-hy-droxy group forms an intra-molecular O-H⋯N(oxime) hydrogen bond. In compound ( ), inter-molecular O-H(oxime)⋯O(hydrox-yl) hydrogen bonds generate (14) dimers, related by inversion centres. In compound , inter-molecular O-H(oxime)⋯O(4-hy-droxy) hydrogen bonds generate 9 chains along the -axis direction, while O-H(4-hydrox-yl)⋯O(2-hydrox-yl) inter-actions form zigzag 6 spiral chains along the c-axis direction, generated by a screw axis at 1, , 1/4: the combination of the two chains provides a bimolecular sheet running parallel to the axis, which lies between 0-1/2 and 1/2-1 . In compound , similar 9 chains, along the axis direction are generated by O-H(oxime)⋯O(4-meth-oxy) hydrogen bonds. Further weaker, C-H⋯π (in ), π-π (in ) and both C-H⋯π and π-π inter-actions (in ) further cement the three-dimensional structures. Hirshfeld surface and fingerprint analyses are discussed.