Incidental abnormalities or findings on brain scans are commonly present in both clinical and research contexts. These unexpected findings are often discovered in patients with headache undergoing computed tomography or magnetic resonance imaging, but their clinical significance and relationship with different headache types are not well understood. Incidental abnormalities can be broadly categorized as clinically significant or nonsignificant. In headache disorders, the most discussed types include the white matter hyperintensities, infarcts, pineal gland cysts, vascular abnormalities, enlarged perivascular spaces, cerebral microbleeds, and pituitary tumors. Different neuroimaging sequences are required to detect different abnormalities. As an example, T2-weighted sequences, particularly with fluid-attenuated inversion recovery, are better for white matter abnormalities. In contrast, susceptibility-weighted imaging is more sensitive to cavernous malformations and microbleeds. In headache disorders, incidental findings do not appear to be overall more prevalent than in the general population. In the case of migraine, the evidence regarding the role of white matter hyperintensities is inconsistent, with several early studies remaining unreplicated. Similarly, reports of infarcts in migraine with aura lack consistent support. In other conditions, such as tension-type headache, post-traumatic headache, and cluster headache, the available data is either scarce, methodologically problematic, or does not indicate a higher prevalence of incidental findings.