The involvement of miR‐204 in lung cancer development is unclear. In our study, we analyzed the expression of miR‐204 in tumor‐ and adjacent‐tissue samples from 141 patients with non‐small cell lung cancer (NSCLC). MiR‐204 expression was decreased in tumor samples compared with non‐cancerous tissue‐derived controls. Moreover, miR‐204 expression negatively correlated with homeobox protein SIX1 expression, tumor size and metastasis. MiR‐204 silencing in miR‐204‐positive NSCLC cell lines promoted cell invasion and proliferation. Concomitantly, MiR‐204 overexpression resulted in reduced cell proliferation and invasion, upregulated E‐cadherin and downregulated N‐cadherin and Vimentin expression. SIX1 was identified as a potential target of miR‐204, and SIX1 silencing partially compromised the invasive and proliferative capacity of miR‐204‐deficient cells. Thus, miR‐204 may be involved in the NSCLC development.