As a prevalent industrial material and component of consumer products, bisphenol A (BPA) is linked to hormone homeostasis disruption and potential carcinogenicity. However, the precise mechanisms through which BPA contributes to thyroid carcinogenesis, especially in papillary thyroid carcinoma (PTC), are not fully understood. This study investigates how BPA boosts the proliferation and tumorigenic characteristics of thyroid cells. BPA exposure significantly increased cell proliferation in a duration-dependent manner at a concentration of 0.5 μM, which is slightly higher than human exposure levels. Therefore, this study utilized BPA treatment concentrations of 0.1 µM and 0.5 µM. BPA augmented the invasiveness of PTC cells with a dependency on both dosage and temporal factors. RNA-seq and gene expression analysis from normal human thyroid follicular epithelial cells suggested that BPA upregulated genes related to oxidative stress and thyroid cancer. Concurrently, our study revealed significant upregulation of NOX4 in thyroid tumors compared to normal thyroid tissues, with higher expression levels observed in advanced carcinomas by analyses of the TCGA database. BPA induces the upregulation of NOX4 in human thyroid cells, thereby triggering the activation of MAPK and PI3K/AKT pathways. In xenograft models, BPA treatment resulted in increased tumor size and Ki-67 proliferation index, accompanied by upregulated NOX4 expression. Additionally, BPA exposure led to higher levels of free triiodothyronine (FT