microRNAs (miRNAs) have been revealed to participate in the pathological process of atherosclerosis (AS). However, the exact role of miR‐338‐3p, a target miRNA of BMP and activin membrane‐bound inhibitor (BAMBI), and its possible molecular mechanism in AS remain unidentified. In this study, we found that BAMBI was significantly decreased, whereas miR‐338‐3p increased in patients with AS and oxidized low‐density lipoprotein (ox‐LDL)‐induced HUVEC cells. Furthermore, overexpression of miR‐338‐3p significantly decreased cell viability and elevated cell apoptosis, whereas its inhibition significantly promoted cell viability and inhibited cell apoptosis in ox‐LDL‐induced HUVEC cells. Moreover, miR‐338‐3p overexpression increased TGF‐β/Smad pathway activation in ox‐LDL‐induced HUVEC cells. A dual‐luciferase reporter assay confirmed the direct interaction between miR‐338‐3p and the 3′‐untranslated region of BAMBI messenger RNA. Furthermore, the suppression of BAMBI ameliorated the effect of miR‐338‐3p inhibition against ox‐LDL‐induced HUVEC cell injury. In conclusion, our study thus suggests that miR‐338‐3p promoted ox‐LDL‐induced HUVEC cell injury by targeting BAMBI and activating the TGF‐β/Smad pathway, which may provide a novel and promising therapeutic target for AS.