Muscle-invasive bladder cancer has traditionally been treated with radical cystectomy and pelvic lymph node dissection. However, trimodality treatment, consisting of maximal transurethral resection of the bladder tumour followed by radiotherapy with concurrent radiosensitisation, has emerged as an effective bladder-preserving alternative for selected patients. As oncological outcomes after trimodality treatment appear comparable to those of radical cystectomy in appropriately selected patients, quality of life has become a key consideration in treatment selection. This review summarizes the current evidence regarding quality of life after trimodality treatment and compares these outcomes with those reported after radical cystectomy. We discuss the principal patient-reported outcome measures used in bladder cancer and review data on urinary, bowel, sexual, and global health-related quality of life following both treatment approaches. Available evidence indicates that quality of life after trimodality treatment typically declines during treatment but recovers to baseline within approximately six months in most patients. Long-term survivors generally maintain satisfactory urinary and bowel function and good overall quality of life. Comparative prospective studies suggest similar overall health-related quality of life between trimodality treatment and radical cystectomy, with bladder preservation offering advantages in body image and sexual function. Although current evidence is limited by heterogeneous study designs, quality of life should be considered alongside oncological outcomes when counselling patients with muscle invasive bladder cancer. Future prospective studies using standardized patient-reported outcome measures and longer follow-up are needed to further refine treatment decision-making.