The study area in this research is East and Northeastern Iran. We present results of S receiver function analysis in this area. For this reason, we used about 1000 teleseismic events of 16 seismic stations belonging to Institute of Geophysics, University of Tehran (IGUT) and 6 seismic stations belonging to International Institute of Earthquake Engineering and Seismology (IIEES). Events with magnitudes greater than 5.7 (mb) at epicentral distances between 60° and 85° were utilized for calculating the S receiver functions. Our results suggest the existence of Moho about 50 km depth and relatively thin lithosphere of about 90 km depth beneath Northeastern Iran. Furthermore, our results clearly show Moho depth of about 40 km and a shallow lithosphere-asthenosphere boundary at about 80 km depth beneath East Iran.