BACKGROUND: Lung cancer is a common cancer. Exosomes are emerging mediators of intercellular communication, and miRNAs serve a crucial position in cancer progression. This project intends to discover whether exosomal miR-454-3p affects tumor progression and its underlying mechanisms. METHODS: Exosomes were isolated utilizing ultracentrifugation. The exosomal biomarkers level was monitored by western blot (WB). The miR-454-3p levels were assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR), and HHEX expression were detected by qRT-PCR and WB. Cell growth and metastasis were detected through CCK-8, colony formation assay and transwell. Meanwhile, the dual luciferase reporter system and immunoprecipitation (RIP) assay was applied to clarify the interactions between miR-454-3p and HHEX. RESULTS: We successfully isolated serum exosomes from NSCLC patients. Then, our team discovered that miR-454-3p was elevated in serum-derived exosomes from NSCLC patients. Functional analysis disclosed that exosomes accelerated NSCLC cell proliferation and metastasis. Silencing of exosomal miR-454-3p hindered NSCLC cell proliferation and metastasis. Subsequently, the starbase database declared that miR-454-3p was interacted with HHEX. HHEX overexpression reversed the promotion of NSCLC cell proliferation and metastasis by exosomal miR-454-3p. CONCLUSIONS: Exosomal miR-454-3p enhanced the progression of NSCLC cells through HHEX. miR-454-3p may be a therapeutic target for NSCLC.