Long noncoding RNAs (lncRNAs) play critical roles in the pathogenesis of various diseases, including a variety of tumors. Nevertheless, its functional roles and underlying molecular basis for their dysregulation in lung adenocarcinoma (LUAD) are largely unknown. Herein, in our study, we identified that lncRNA TMPO-AS1 is significantly upregulated in LUAD tissues and cell lines. Knockdown of TMPO-AS1 remarkably suppressed LUAD cell growth, induced apoptosis as well as G1/S arrest, and inhibited LUAD cell invasion, whereas overexpression of TMPO-AS1 exerts the opposite effects. Next, we implemented online database analysis tools to find that mir-383-5p could target TMPO-AS1, and our data showed that TMPO-AS1 was negatively correlated with mir-383-5p in LUAD specimens. We found that inhibiting miR-383-5p expression led to a marked upregulation of TMPO-AS1 level, while overexpression of miR-383-5p markedly suppressed TMPO-AS1′s expression and function, suggesting that TMPO-AS1 is negatively regulated by miR-383-5p. In addition, we confirmed that miR-383-5p directly targeted TMPO-AS1 by binding to microRNA binding sites in the TMPO-AS1 sequence with a luciferase reporter and RIP assays. Besides, the inhibition of TMPO-AS1 significantly suppressed the tumorigenesis ability of LUAD cells in vivo. Together, these results demonstrate that TMPO-AS1 could be considered as a potential therapeutic target for LUAD patients.