Patient-derived organoids (PDOs) are valuable 3D tumor models, retaining primary tumor characteristics, but their use is limited by small sample volumes and the absence of tailored platforms. This study introduces an agarose microwell platform for PDO-based tumor and tumor microenvironment models, facilitating rapid drug screening with minimal samples. The 3D-printed microwells support co-culture spheroids of non-small cell lung carcinoma (NSCLC) cells and PDOs with fibroblasts. The platform produces uniformly-sized, viable spheroids with fibroblast-induced drug resistance. PDOs maintain viability and proliferation, showing reduced cytotoxicity to a specific inhibitor in the presence of fibroblasts or their supernatant. This platform proves suitable for in vitro tumor modeling and assessing drug efficacy with patient-derived tissues.