microRNAs (miRNAs), a class of small non-coding RNA molecules, can regulate gene expression by interacting with the 3'-untranslated regions (3'UTR) of target genes and influence various biological processes. We investigated the potential role of miR-24-3p in the development of bladder cancer by regulating DEDD, a member of the death effector domain-containing protein family. First, we found that miR-24-3p was highly expressed and that DEDD was expressed at a low level in bladder cancer tissues compared with that in adjacent bladder tissues by qRT-PCR (P<0.0001). Second, we found that miR-24-3p promoted the proliferation ability of bladder cancer cells using the MTT assay and colony forming assay; and showed that miR-24-3p accelerated the migration and invasion of bladder cancer cells using migration and invasion assays (P<0.05). Moreover, miR-24-3p inhibited apoptosis of bladder cancer cells, as shown by flow cytometry (P<0.05). Western blot results demonstrated that miR-24-3p participated in autophagy of bladder cancer cells by DEDD. In addition, the tumor formation assay showed that miR-24-3p promoted the growth of bladder tumor in vivo. Furthermore, the luciferase reporter gene assay indicated that miR-24-3p suppressed DEDD gene transcription. Therefore, our study indicated that miR-24-3p promoted bladder cancer progression by inhibiting DEDD.