INTRODUCTION: ABL2 contributes to the oncogenic potential of cancers, pointing to its inhibition as a possible strategy against malignant diseases. Bioinformatics prediction of upstream effector miR-30a-5p for ABL2 allowed us to hypothesize and then validate mechanistic actions of miR-30a-5p in lung adenocarcinoma (LUAD). MATERIALS AND METHODS: The ABL2 expression in LUAD was analyzed in the TCGA data, clinical samples, and cell lines. The shRNA-mediated silencing of ABL2 was introduced to illustrate its effect on malignant phenotypes of LUAD cells. The binding affinity between ABL2 and miR-30a-5p was verified by luciferase activity and RNA pull-down assay. Ectopic expression, knockdown methods, and PI3K inhibitor LY294002 were used to investigate their effects on in vitro biological characteristics and in vivo tumor growth of LUAD cells. Using nude mouse lung adenocarcinoma in situ and brain metastasis models to validate the inhibitory effect of miR-30a-5p on LUAD by regulating the ABL2/PI3K/AKT signaling axis. RESULTS: High expression of ABL2 and poor expression of miR-30a-5p were noticed in LUAD tissues and cell lines. Importantly, miR-30a-5p was demonstrated to target and downregulate ABL2, subsequently inactivating the PI3K/AKT pathway. miR-30a-5p inhibited the malignant phenotypes of LUAD cells by inhibiting ABL2 expression and inactivating the PI3K/AKT pathway. For in vivo experiments, miR-30a-5p was substantiated to thwart tumor tumorigenesis by regulating the ABL2/PI3K/AKT axis. In addition, miR-30a-5p suppresses the occurrence and development of in situ lung cancer and brain metastasis via the ABL2/PI3K/AKT signaling pathway. CONCLUSION: This study underscores the inhibitory role of miR-30a-5p in LUAD through the ABL2/PI3K/AKT axis, which may be a viable target for LUAD treatment.