In situ gels have become one of the most prominent and accessible systems. These systems have several advantages like simple manufacturing, easy to use, improved adherence, and patient comfort by minimizing drug administration frequency by its unique characteristic features of sol to gel transition. In the 'sol-gel' method, the precursor goes through hydrolysis and polymerization or condensation to produce a colloidal suspension or solution. As they can administer in solution form, these in situ gelling systems undergo gelation at the achievement site. Some researchers recently developed in situ gelling systems of liposomes, microspheres, nanoemulsions, nanospheres, etc. This review mainly focused on the introduction, advantages, disadvantages, types of polymers, and suitable characteristics for preparing in situ gels.