MiR-19b-3p has been reported in several types of human cancer. Nevertheless, the expression profile and biological functions of miR-19b-3p remain unclear in non-small cell lung cancer (NSCLC). The expression level of miR-19b-3p was evaluated in NSCLC tissues and cell lines using qRT-PCR. Survival analysis was performed using Kaplan-Meier curves, while the prognostic significance of miR-19b-3p was analyzed using Cox regression analysis in 80 NSCLC patients. The effects of miR-19b-3p on cell proliferation and invasion capacities were analyzed using CCK-8, crystal violet, and transwell assays. Target genes of miR-19b-3p were assessed using luciferase reporter assay, qRT-PCR, Western blot and rescue experiments. MiR-19b-3p was found to be upregulated in human NSCLC tissues and cell lines. The expression of miR-19b-3p was observed to be closely associated with TNM stage and metastasis. High expression of miR-19b-3p was found to be capable of predicting poor clinical prognosis in NSCLC patients. Whilst overexpression of miR-19b-3p was demonstrated to promote the proliferation and invasion of NSCLC cells, knockdown of miR-19b-3p showed an opposite inhibitory effect. Bioinformatics analysis and luciferase reporter assays confirmed that HOXA9 is a direct target of miR-19b-3p. Functional assays demonstrated that NSCLC cell proliferation and invasion were promoted by miR-19b-3p via negative regulation of HOXA9. Finally, overexpression of HOXA9 was shown to partially reverse the tumor promoting effect of miR-19b-3p. This study indicates that miR-19b-3p is a crucial prognostic biomarker of NSCLC, and that targeting of the miR-19b-3p/HOXA9 axis may be a promising strategy in NSCLC therapy.