Background: Hyaluronic acid (HA) instillation has emerged as a potential alternative treatment for Bacillus Calmette–Guérin (BCG)-induced cystitis, a common complication of BCG intravesical therapy for non-muscle-invasive bladder cancer (NMIBC). BCG-induced cystitis presents with symptoms similar to bacterial infections, such as urinary urgency, frequency, and pain. Conventional treatments, such as BCG discontinuation, antibiotic therapy, and corticosteroid use, are often insufficient. HA therapy works by restoring the bladder’s glycosaminoglycan layer, reducing inflammation, and promoting tissue repair. Objectives: This narrative review assessed the efficacy and safety of HA in managing BCG-induced cystitis based on a literature search of PubMed, Google Scholar, and Cochrane databases, identifying seven relevant studies. Conclusion: HA treatment has been associated with improvements in bladder symptoms, including reductions in pain, urgency, and frequency, as well as an increase in bladder capacity. Combination treatments with chondroitin sulfate or pirarubicin demonstrated superior outcomes compared to HA alone. While the studies reported minimal adverse effects, variability in study design, sample sizes, and follow-up durations limited the strength of the evidence. These findings suggest that HA can be safely administered to NMIBC patients alongside BCG therapy with minimal side effects and no adverse impact on treatment outcomes.