Objective To investigate the molecular mechanism of miR-338-3p in the proliferation, migration, invasion, and apoptosis of esophageal cancer cells and its targeted regulation of WNK1. Methods Human normal esophageal epithelial cell line Het-1A and human esophageal cancer cell lines Eca-109, EC-1, and EC9706 were cultured in vitro. The expression levels of miR-338-3p and WNK1 were measured by qRT-PCR and Western blot, respectively. In EC9706 cells, miR-con, miR-338-3p mimics, si-con, si-WNK1, miR-338-3p mimics and pcDNA, and miR-338-3p mimics and pcDNA-WNK1 were transfected into EC9706 cells. MTT assays were used to detect cell proliferation, flow cytometry was used to detect apoptosis, and Transwell assays were used to detect migration and invasion abilities. A dual luciferase reporter assay was used to assess the relationship between miR-338-3p and WNK1. Results Compared with Het- 1A, the expression levels of miR-338-3p in esophageal cancer cell lines Eca-109, EC-1, and EC9706 were reduced significantly (P<0.05) and the expression levels of WNK1 mRNA and protein were increased significantly (P< 0.05). Transfection of miR-338-3p mimics or si-WNK1 significantly reduced the viability, migration, and invasion of EC9706 cells (P<0.05), and increased the apoptosis rate of EC9706 cells (P<0.05). The dual luciferase reporter assay confirmed that miR-338-3 targeted WNK1. Cotransfection of miR-338-3p mimics and pcDNA-WNK1 obviously reversed the effects of miR- 338-3p mimics on cell proliferation, migration, invasion, and apoptosis. Conclusions MiR-338-3p downregulates WNK1 in esophageal cancer, thereby inhibiting the proliferation, migration, and invasion of esophageal cancer cells and inducing apoptosis.