Prostate cancer (PCa) is the most frequently diagnosed malignant tumor in males, and there are currently few effective therapeutic targets following hormone therapy resistance. Subunits of eukaryotic initiation factor 3 (eIF3) have been implicated in the progression of various cancers. This study aims to investigate the biological functions of the eIF3m subunit in PCa and assess its potential as a novel therapeutic target for treatment. We utilized open-access datasets and patient tissues to analyze the expression and prognostic value of eIF3m in PCa. To explore the role of eIF3m in PCa growth, we established eIF3m knockdown models in PC3 and 22Rv1 cells for both in vitro and in vivo studies. Gene set enrichment analysis (GSEA) was utilized to identify signaling pathways regulated by eIF3m in PCa. Additionally, western blotting and immunochemistry were used to confirm the regulation of c-Myc signaling by eIF3m in PCa. Our results indicated that eIF3m expression was elevated in PCa tissues, with higher levels correlating with an increased risk of biochemical recurrence following radical prostatectomy. Both in vitro and in vivo experiments demonstrated that inhibiting eIF3m significantly impeded the growth of PCa cells. GSEA and immunochemistry further revealed that high eIF3m expression contributed to the activation of c-Myc signaling in PCa patients. Notably, the downregulation of eIF3m resulted in a significant decrease in the expression of c-Myc mRNA and protein in PCa cells. Overall, our findings suggest that eIF3m inhibition significantly suppressed PCa cell growth and c-Myc signaling, indicating that eIF3m is a promising therapeutic target for PCa patients.