Background and Purpose: The risk of epilepsy after stroke has not been thoroughly explored in pediatric ischemic stroke. We examined the risk of epilepsy in children with ischemic stroke as well as in their first-degree relatives. Methods: In Swedish National Registers, we identified 1220 children <18 years with pediatric ischemic stroke diagnosed 1969 to 2016, alive 7 days after stroke and with no prior epilepsy. We used 12 155 age- and sex-matched individuals as comparators. All first-degree relatives to index individuals and comparators were also identified. The risk of epilepsy was estimated in children with ischemic stroke and in their first-degree relatives using Cox proportional hazard regression model. Results: Through this nationwide population-based study, 219 (18.0%) children with ischemic stroke and 91 (0.7%) comparators were diagnosed with epilepsy during follow-up corresponding to a 27.8-fold increased risk of future epilepsy (95% CI, 21.5–36.0). The risk of epilepsy was still elevated after 20 years (hazard ratio [HR], 7.9 [95% CI, 3.3–19.0]), although the highest HR was seen in the first 6 months (HR, 119.4 [95% CI, 48.0–297.4]). The overall incidence rate of epilepsy was 27.0 per 100 000 person-years (95% CI, 21.1–32.8) after ischemic stroke diagnosed ≤day 28 after birth (perinatal) and 11.6 per 100 000 person-years (95% CI, 9.6–13.5) after ischemic stroke diagnosed ≥day 29 after birth (childhood). Siblings and parents, but not offspring, to children with ischemic stroke were at increased risk of epilepsy (siblings: HR, 1.64 [95% CI, 1.08–2.48] and parents: HR, 1.41 [95% CI, 1.01–1.98]). Conclusions: The risk of epilepsy after ischemic stroke in children is increased, especially after perinatal ischemic stroke. The risk of epilepsy was highest during the first 6 months but remained elevated even 20 years after stroke which should be taken into account in future planning for children affected by stroke.