Abstract: Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized by chronic hyperglycemia, hyperlipidemia, and peripheral insulin resistance. Endoplasmic reticulum stress (ERS), a response to cellular stress, is activated across various tissues during the progression of T2DM, leading to disruptions in protein synthesis. Notably, epithelial and endocrine cells with hormone-secreting functions are particularly vulnerable to functional impairments induced by ERS. The gut-pancreas axis is essential for regulating metabolism and the progression of T2DM. Intestinal epithelial L cells, integral to the intestinal barrier, can secrete the glucagon-like peptide-1 (GLP-1). This hormone promotes insulin secretion from pancreatic β-cells and plays a critical role in glucose metabolism. Importantly, ERS plays a critical role in regulating glucolipid-induced dysfunction of gut-pancreas axis. For instance, ERS is involved in regulating the intestinal barrier and the secretion of GLP-1 as well as insulin. Therefore, ERS can be a potential target for T2DM treatment. In this paper, we review the regulatory roles of ERS in the gut-pancreas axis during the development of T2DM, and summarize the therapeutic drugs and strategies targeting ERS for T2DM treatment.