AbstractSilver sulfide (Ag2S) chalcogenide compound can be a viable absorber in the applications of thin film solar cells owing to its optimum bandgap of 1.1 eV and high absorption coefficient. Herein, we propose a novel Ag2S‐based n‐CdS/p‐Ag2S/p+‐SnS double‐heterojunction solar cell. The numerical analysis of the device has been performed with SCAPS‐1D (Solar Cell Capacitance Simulator). In the case of single heterojunction, n‐CdS/p‐Ag2S manifests an efficiency of 19.75%, where VOC = 0.66 V, JSC = 36.99 mA/cm2 and FF = 81.50%. However, Ag2S‐based double‐heterojunction device with optimized structure provides the efficiency of 29.51% with VOC = 0.81 V, JSC = 42.81 mA/cm2 and FF =85.24%. The noteworthy augmentation of VOC and JSC in double‐heterojunction results from the reduction in surface recombination velocity and rise in built‐in voltage in the p‐Ag2S/p+‐SnS hetero‐interfaces that promote the higher efficiency of the device. These theoretical insights indicate a path for fabrication of an efficient Ag2S based thin film solar cell.