The influence of a bending strain on the contact angle and the mechanical surface tension gamma of single-crystal silicon has been considered. The change in the contact angle has been explained on the basis of the thermodynamic theory of the wetting of deformable solid surfaces. Negative values of gamma SL and gamma SV have been obtained for strained silicon. The total force of the stresses in the bulk of the solid gamma S must be taken into account in balancing the forces on a line of three-phase contact.