Glioblastoma multiforme (GBM) is a highly aggressive brain tumor that has a poor prognosis due to tumor recurrence and lack of effective treatment options. In order to address this challenge, we developed a novel 3D in vitro model of GBM that incorporates a co-culture of human iPSC-derived brain organoids with patient-derived GBM cells and its tumor microenvironment components. This system enables the investigation of mechanisms that lead to chemotherapy resistance and facilitates the detection of potential therapeutic agents for GBM. To establish this model, we genetically engineered patient derived GBM cells with a secreted luciferase construct to monitor live cell survival following different therapeutic treatments. The cells were then co-cultured with iPSC-derived brain organoids, and over a period of 15-40 days, both cell lines invaded and grew extensively into the organoid. Subsequently, the 3D Glio-organoids were treated with standard of care therapeutic agents at different dosages and compared to traditional 2D growth cell cultures. Our results demonstrate that this co-culture model is an optimal system for studying the mechanisms of GBM cells' interactions with the tumor microenvironment. The use of brain organoids that enable the simulation of the tumor microenvironment presents a powerful tool for investigating GBM pathogenesis. Overall, our 3D in vitro model of GBM provides an innovative approach to improve preclinical models of glioblastoma, thereby offering opportunities for novel therapeutic interventions.