Objective: MicroRNA (miR)-147a acts as an inhibitory miRNA in many cancers. However, its potential roles in non-small-cell lung cancer (NSCLC) remain unclear. Methods: Levels of miR-147a and C-C motif chemokine ligand 5 (CCL5) were measured using a quantitative real-time PCR assay. Cell growth, migration, and invasion of NSCLC cells were assessed by colony formation, wound healing, and Transwell invasion assays, respectively. The role of miR-147a in the growth and metastatic ability of NSCLC in vivo was detected using a xenograft model and experimental lung metastasis model. Results: miR-147a was downregulated in NSCLC cell lines as well as in tissues. Gain-of-function and loss-of-function analyses demonstrated that upregulation of miR-147a decreased the aggressiveness of NSCLC cells in vitro. In addition, CCL5 was identified as a target of miR-147a. We also demonstrated the effect of miR-147a in the progression of NSCLC cells via targeting CCL5. Finally, the in vivo mouse xenograft model showed that miR-147a inhibited progression of NSCLC cells. Conclusions: Overall, expression of miR-147a was downregulated in NSCLC. Importantly, upregulation of miR-147a suppressed the growth and metastasis of NSCLC cells in vivo by targeting CCL5.