The progression of hepatocellular carcinoma (HCC) is partly driven by reactive oxygen species (ROS)-induced tissue damage and inflammation. Nicotinamide adenine dinucleotide phosphate oxidases (NOXs) are key regulators of ROS production, yet the specific role of NOX1 in HCC progression and therapeutic response remain incompletely understood. In this study we investigated the critical role of NOX1 in progression, metastasis and therapeutic sensitivity of HCC, and explored its potential as a therapeutic target. By comprehensive analysis of public databases and validation with in-house clinical specimens, we showed that NOX1 expression was significantly elevated in metastatic HCC that was correlated to poor patient prognosis. Knockdown of NOX1 or pharmacological inhibition with a selective NOX1 inhibitor ML171 significantly reduced ROS production and suppressed HCC cell motility and invasion in vitro. NOX1 inhibition also attenuated HCC metastasis in experimental metastasis mouse model using direct injection of HCC cells, and mitigated CCl-induced liver injury and pro-tumorigenic microenvironment in CCl-induced chronic liver injury and spontaneous tumor development mouse model. Importantly, we demonstrated that combined sorafenib or radiotherapy with NOX1 inhibition synergistically reduced the metastatic potential of HCC cells and enhanced the therapeutic efficacy. Bioinformatics analysis revealed that NOX1 contributed to HCC metastasis and therapy resistance by modulating ROS homeostasis, cellular antioxidant systems and inflammatory pathways. Taken together, this study elucidates the critical role of NOX1 in HCC pathogenesis, suggesting that NOX1 inhibition represents a promising strategy to overcome resistance and enhance HCC sensitivity to sorafenib and radiotherapy.