The semiconducting SnS heterojunctions have been used as solar cell structure. In an effort to study the photovoltaic properties of different SnS heterojunctions, in this work, the CdS/SnS, ZnS/SnS, ZnO/SnS, a-Si/SnS, and SnS/c-Si heterojunctions were studied by numerical analysis. The calculated results show that the ZnS/SnS heterojunction has the highest conversion efficiency. The SnS thin film has different roles depending on another material. The heterojunction structure will affect the window and absorption properties. The less absorption in the window layer and the less photo-generated carrier barrier in the heterojunction interface will lead to the improved photovoltaic properties. The photovoltaic properties can be further enhanced by adjusting the thickness. The calculated results provide a guide to the design and fabrication of SnS heterojunction solar cells. (C) 2013 Elsevier Ltd. All rights reserved.