Glioblastoma is one of the most common and aggressive primary brain tumors, displaying poor survival rates and little success in clinical trials. Following the conventional treatments, which include surgical resection, radiotherapy, and chemotherapy, the average survival time for patients remains low, and even in those who respond to first-line treatments, the tumor eventually recurs. Additionally, due to the sensitive location of these tumors and their infiltrative nature, many patients undergo partial resection, leaving the remaining cells to grow and recolonize the brain. For this reason, models that recapitulate the treatment of patients after surgery have become essential. This protocol describes the resection of tumors in mice following cell injection to the cortex. We recommend that the day of resection be adjusted to the cell line latency and tumor size. This model can be used for assessing the success of different therapeutic strategies and their appropriate timing in combination with surgical resection.