Introduction: The aim of the study was to investigate the potential mechanism of specificity protein 1 (SP1) in bladder cancer progression through the PTEN-mediated AKT/mTOR pathway. Methods: Human bladder cancer cell lines (HT-1197, HT-1376, and T24) and normal ureteral epithelial cell line SV-HUC-1 were used. SP1 expression was detected via quantitative real-time PCR and Western blotting. Cell viability, migration, invasion, and apoptosis were assessed using CCK-8, transwell, and flow cytometry assays, respectively. The involvement of the PTEN-mediated AKT/mTOR pathway was evaluated by Western blot. A mouse xenograft model was built, and immunohistochemical staining was applied to visualize SP1 and Ki67 expression in tumor tissues. Results: SP1 was overexpressed in bladder cancer cells. SP1 knockdown inhibited viability, migration, and invasion and promoted apoptosis in bladder cancer cells. PTEN intervention increased cell viability, migration, and invasion and decreased apoptosis, which was reversed by SP1 knockdown. The activation of the AKT/mTOR pathway resulting from PTEN knockdown was attenuated by SP1 knockdown. In vivo results showed that SP1 knockdown suppressed tumor growth, increased PTEN expression, and decreased AKT/mTOR pathway-related protein levels. Conclusion: SP1 promotes bladder cancer progression by inhibiting the PTEN-mediated AKT/mTOR pathway. Targeting SP1 may be a potential therapeutic strategy for treating bladder cancer.