Gliomas are the most common tumors found in the central nervous system. They are classified based on their histopathological malignancy. Low-grade gliomas (LGG) can turn into glioblastomas (GBM), the most aggressive form of brain cancer with the worst prognosis. Previous studies have shown that microtubule-associated protein tau (MAPT) is increased in GBM and that reducing it can improve survival in animal models. On the other hand, elevated MAPT expression has been linked to increased survival in LGG, indicating its potential as a survival biomarker. However, previous studies have primarily focused on the canonical protein-coding transcripts and gene-level expression of MAPT, disregarding the diversity of its many isoforms. Many diseases in almost every tissue have been associated with a dysregulation of alternative splicing, either through an altered ratio of the expressed isoforms or by expressing aberrant transcripts with different alternative transcription start and termination sites. This study investigates the association of specific MAPT transcripts with survival in LGG and GBM using publicly available genomic datasets and performing statistical analyses. The results of the study indicated coding and several non-coding isoforms associated with overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI). After including the relevant predictors as covariates, it was observed that among the protein-coding isoforms, MAPT-205 and MAPT-201 were significantly associated with clinical survival endpoints, but with opposite trends. These findings highlight the importance of studying the role of MAPT isoforms in glioma cellular phenotypes, aggressiveness, and patient survival.