One of the preferred treatments for bladder cancer, one of the most common cancers worldwide, is cisplatin-based chemotherapy. Since most tumor cells show cisplatin resistance, it is very important to discover new agents without adverse side effects. β-arbutin, a hydroquinone-β-D-glucopyranoside, has biological properties such as antioxidant, antimicrobial, anti-inflammatory, and anticancer, and is a phytochemical widely used as a skin whitener. In this study, β-arbutin was purified from the animal feed plant Onobrychis buhseana Boiss. (sainfoin). The study aimed to investigate the combined effects of cisplatin, a clinically used chemotherapeutic agent, and β-arbutin on HT-1376 bladder cancer cells for apoptosis, cell viability, and migration. In the study, after HT-1376 bladder cancer cells were cultured, optimum β-arbutin and cisplatin doses were determined on HT-1376 cells using the WST-1 test. To determine the apoptotic and migratory effects, flow cytometry and wound healing assays were performed. In HT-1376 cells, β-Arbutin led to greater apoptotoic and migratory effects when used alone and combined with Cisplatin (p < 0.0001 for apoptotic and migratory effects treated with β-Arbutin alone, p < 0.0001 for apoptotic and migratory effects when combined with Cisplatin). As a result, it can be suggested that β-arbutin may be a good drug candidate for treating bladder cancer.