This is a phase 1, multicenter, open-label study of talimogene laherparepvec in pediatric subjects with advanced non-CNS tumors that are amenable to direct injection in the clinical setting. Approximately 18 treated pediatric subjects are expected to be enrolled into 2 cohorts stratified by age (permissible based on the incidence of DLTs, a minimum of 6 subjects/cohort and a minimum of 18 subjects total). DLT will be evaluated based on 6 to 12 DLT-evaluable subjects in each cohort. The DLT evaluation period is 35 days from the initial administration of talimogene laherparepvec.