In today's scenario, as the development is taking place simultaneously the demand for the electricity in the world is also increasing. Operation and planning of large interconnected power systems are becoming more and more complex. In power system, voltage stability plays a very important role. Voltage instability may cause blackouts and collapse of the power system. In last decade, many countries have experienced the problem of blackouts due to voltage instability. The problem of voltage stability is mainly caused due to stressed loading condition of the system. It is essential to analyse the voltage stability for improvement in the efficiency of power system. Various authors have conducted research on analysis of voltage stability and methods to improve it. This paper, presents a review on research and development in the voltage stability analysis and methods for improving the voltage stability.