Exposure to ionizing radiation (IR) is a common occurrence in clinical practice and incidents involving nuclear detonation or nuclear reactor accidents. IR triggers cellular events that result in oxidative stress and damage to macromolecules, rendering it harmful. While the central nervous system (CNS) was once believed to be resistant to radiation, emerging evidence suggests that even small doses of IR can adversely impact the brain. Exposure to an unsafe dose of radiation can cause increased permeability of the blood-brain barrier (BBB), neuronal apoptosis, reduced neurogenesis, impaired synaptic plasticity, and cognitive dysfunction. In recent years, the potential benefits of dietary agents and phytochemicals for mental health and radiation-induced damage have been widely investigated. Despite this, few studies have explored the protective effects of plants against radiation-induced brain damage. Here, we present a review collating evidence on the beneficial effects of dietary plants on radiation-induced brain damage based on behavioral studies. Notably, Amaranthus paniculatus, Grewia asiatica, Lycium barbarum, and phytochemicals such as vitamin E, corilagin, curcumin, resveratrol, and ursolic acid have demonstrated potential in mitigating radiation-induced damage to the CNS. Furthermore, preliminary studies have indicated that alpha-tocopherol and the micronutrient selenium have neuroprotective effects in cancer survivors previously treated with radiation to the brain. This review focuses exclusively on behavioral outcomes to assess the impact of ionizing radiation on the CNS and the effectiveness of dietary plants and phytochemicals as neuroprotective agents against radiation-induced neuronal damage.