Background: Pathogenic variants in SYNGAP1causedevelopmental and epileptic encephalopathy (DEE) and intellectual disability. Seizures are medically refractory and there is limited evidence on the use of corpus callosotomy (CC) and vagal nerve stimulation (VNS). Methods: A retrospective study was completed examining the effectiveness of VNS and CC in children with SYNGAP1-DEE using the SynGAP Research Database and an additional child followed at our centre. Results: Fifteen patients from the SynGAP Database were included. Of those who had VNS (n=11), 7 children had an >50% reduction in seizure frequency (n=7/11, 64%), 2 had worsening (n=2/11, 18%), 1 had no change (n=1/11, 9%), and 1 had an unknown response (n=1/11, 9%). Two children had CC only, 1 had complete seizure freedom, and 1 had a >50% reduction. Two children underwent VNS and CC, 1 had a >50% reduction in seizure frequency and the other had no change. One child followed at our centre experienced a sustained >80% reduction in seizure frequency following CC (i.e., after 1.5 years). Conclusions: We provide the first in-depth description of the response to VNS and CC in children with SYNGAP1-DEE, and provide insight into the use of of palliative surgical procedures in this population.