Potassium (K) is an important nutrient that helps plants maintain their vitality and growth processes. But a huge fraction of K in soil is in fixed form and inadequately available for plants. Therefore, K-based chemical fertilizers provide a sufficient amount of K for plants and have a positive impact on plants in terms of yield. However, on the contrary, the intensive application of chemical-based fertilizers shows negative impacts on the environment. Application of potassium solubilizing bacteria (KSB) presents an eco-friendly approach to assisting plants in the uptake of the soluble fraction of K. KSB solubilizes the insoluble form of K in soil through the production of organic acids, protons, polysaccharides, etc. The biofertilizers based on KSB can be used for sustainable agriculture. This article illustrates a general introduction of KSB, their K solubilizing mechanism, and their use as biofertilizers as an eco-friendly approach.