We have analyzed the horizontal particle motion of borehole guided waves from three-component vertical seismic profile data recorded from three experiments. The polarization directions of the guided waves are consistent with the direction of horizontal principal stress determined independently. We suggest that stress-induced velocity anisotropy in the rock adjacent to the borehole appears to cause antisymmetric flexural guided modes to be polarized in the direction of the maximum horizontal principal stress. Thus analysis of the horizontal particle motion of borehole guided waves appears to represent a new method for determining the orientation of horizontal principal stresses. ¿ American Geophysical Union 1988