Background <p>MicroRNAs (miRNAs) are key regulators of atherosclerotic (AS) development. This study aimed to evaluate miR-425-5p expression patterns and their clinical relevance in patients with AS.</p> Methods <p>131 patients with AS and 112 controls were enrolled. Serum miR-425-5p and Krüppel-like factor 7 (KLF7) levels were quantified using RT-qPCR. ROC analysis assessed the diagnostic value of miR-425-5p for AS, and logistic regression identified risk factors. An in vitro AS model was established using ox-LDL-stimulated HVSMC cells. Cell viability, apoptosis, inflammatory cytokine secretion, and migration were assessed by CCK-8, flow cytometry, ELISA, and Transwell assays, respectively. Bioinformatics was used to predict the downstream target genes of miR-425-5p, and their targeting bindings were verified by DLR and RIP assays.</p> Results <p>miR-425-5p was significantly upregulated, while KLF7 was downregulated, in serum of AS patients and in ox-LDL-stimulated HVSMCs. Serum miR-425-5p was positively correlated with CIMT, TG, and LDL-C, and negatively correlated with HDL-C. It showed favorable diagnostic performance for AS (85.50% sensitivity, 85.71% specificity) and was identified as an independent risk factor for AS. Moreover, ox-LDL-induced HVSMC dysfunction, including reduced viability, increased apoptosis, elevated migration, and excessive inflammation, was attenuated by miR-425-5p inhibition and further attenuated by KLF7 knockdown.</p> Conclusions <p>Serum miR-425-5p demonstrates diagnostic potential for AS and correlates with HVSMC proliferation, apoptosis, migration, and inflammatory responses.</p>