Glioblastoma (GBM) is the most common and aggressive primary brain tumor. Even with recent developments in immunotherapy, the prognosis for GBM remains poor, and tumor recurrence is inevitable. Consequently, preclinical models for testing new therapies for GBM are critical for developing better treatments. Specifically, for investigating oncolytic viruses, a syngeneic tumor model is necessary so that an immunocompetent host can be used. Here, we describe our protocol for an in vivo murine model to test the efficacy of oncolytic Zika virus to treat high grade gliomas. These methods can be expanded to incorporate other tumor cell lines as well as other oncolytic viruses.