Pediatric GIST (gastrointestinal stromal tumors) are mostly KIT/ PDGFRA-WT and harbor mutations in SDH (succinate dehydrogenase), making them TKI (tyrosine kinase inhibitor) resistant due to the absence of gain-of-function tyrosine kinase mutations. Due to rarity of GIST in children, there have been few clinical trials available for patients with advanced disease, resulting in limited treatment options and a lack of pediatric-specific consensus guidelines. Here, we report the case of a patient with progressive, metastatic SDHB-mutant GIST that displayed a significant clinical response with a combination of Olaparib and TMZ (temozolomide).