Femtocell provides better QoS for indoor mobile users by enhancing the signal strength. For efficient indoor coverage traditional macrocell network is over laid with femtocells. Both this macrocell and the femtocells operate in same frequency band. Spectrum, a limited resource needs to be shared efficiently between macrocell and femtocells. In this approach a method for spectrum sharing between adjacent femtocells is proposed. The decision as to which femtocell will share its allotted spectrum with its neighbouring femtocell to improve the system throughput is crucial. A cooperative bargain game is proposed which helps a femtocell to bargain unutilized spectrum from its adjacent femtocells to efficiently serve its users. Using this game model it is observed that the spectrum is efficiently utilized, increasing the overall throughput of the system. It also reduces the path loss by ∼3.6–5.7% and increases the channel gain by −60.2–65.8%.