The blood-brain barrier (BBB) poses a significant challenge in delivering therapeutic agents to the central nervous system (CNS). Intranasal drug delivery, especially using in situ gelling systems, offers a promising non-invasive route that bypasses the BBB. This review highlights the formulation strategies, polymer selection, mechanism of gelation, and evaluation parameters of nasal in situ gels designed for CNS-active drugs. The use of thermosensitive, pH-sensitive, and ion-activated polymers enables the controlled and sustained release of drugs, improving bioavailability and patient compliance. Furthermore, in situ gels enhance mucosal adhesion and residence time in the nasal cavity, increasing drug transport via olfactory and trigeminal pathways. The review also discusses current challenges and future directions in this evolving field of targeted CNS therapy.