miRNAs are small non-coding RNA molecules, involved in the regulation of gene expression via binding to messenger RNA (mRNA), thereby preventing protein translation. We found that the promotor region of miR-193a is highly methylated in FaDu head and neck cancer cells, assuming that its expression is suppressed. Moreover, our results indicated that miRNA-193a levels are undetectable in biopsies of head and neck cancer patients. Induction of miR-193a expression by treatment with methyltransferase inhibitor or transduction of head and neck squamous cell carcinoma (HNSCC) cells with miR-193a resulted in a significant decrease in cell viability in a dose and time-dependent manners, as well as induction of apoptosis through the caspase intrinsic pathway. Moreover, miR-193a also inhibited tumour growth in xenograft mice transplanted with FaDu cells. In addition, we found that miR-193a inactivates the AKT/mTOR signaling pathway through the downregulation of PIK3R3, mTOR, S6KB2, and ERBB4. These observations suggest that miR-193a plays an important role in tumor biogenesis and therefore has the potential to serve for diagnostics as well as therapeutics in HNSCC.