The gut is an important organ that includes the most surface contact with the outside environment. This massive surface is covered by a layer of epithelial cells that creates a physical barrier to the environment, whilst absorbing nutrients. It is also a major site of commensal microbiota, which works together with gut epithelial and immune cells to maintain the integrity of this vital organ. Impaired inflammatory regulation of the intestine and bowel causes chronic inflammatory disorders such as inflammatory bowel disease (IBD). We currently lack human models that include relevant immune components, so we don’t know how the different cell types in the gut epithelial interact together to form the healthy gut epithelial barrier. The purpose of this study is to investigate the contribution of macrophages to gut epithelial barrier function. We established two in vitro models: 1) Transwell coculture and 2) direct coculture of iPSC-derived macrophages and an epithelial cell line, to test the roles of secreted or contact-mediated factors respectively. The quality of the epithelial barrier is measured by examining polarisation and tight junction formation microscopically, using NF-κB and IRF reporters in the epithelial cells or macrophages to monitor for inflammatory pathway activation, and monitoring of barrier integrity using transepithelial electrical resistance (TEER) as well as dye exclusion assays. We hypothesise that introduction of macrophages to the gut epithelial models will improve the development and integrity of the gut epithelium.