We present the results of a shear wave splitting analysis performed on the teleseismic direct S wave recordings of 63 broadband stations belonging to the Iran-China temporary network to investigate the mantle deformation on the Arabia-Eurasia collision zone in Western Iran. We used the Reference Station Technique to overcome potential contamination from the source-side anisotropy on the direct S-wave signals. The average splitting delay time over the entire region was found to be 1.14 ± 0.42 s for the direct S wave. The fast polarization directions have the northeast-southwest trend in the Alborz region, and in Central Iran, they rotated and showed an east-west trend. In the Zagros, the direction of the fast axes tends to be aligned with the Zagros Mountain and showed a northwest-southeast direction. The direct S-waves, have a larger footprint and therefore average over a larger region, and relative to the SK(K)S phases, are influenced more strongly by the asthenospheric fabric due to their larger angles of incidence, which results in a larger zone of influence for station average anisotropy parameters. We propose that the observed anisotropy is mainly controlled by the LPO fabric developed due to the shearing of the asthenospheric layer in response to the motion of the lithosphere relative to the deeper mantle.