Objective: Lack of palliative care knowledge among caregivers may pose an access barrier for cognitively impaired older adults, who may benefit from the specialized care. Therefore, this study aims to examine the effectiveness of an educational intervention in improving palliative care knowledge among informal caregivers of cognitively impaired older adults. Method: Using a one-group, pre- and post-test intervention design, this study implemented an individual, face-to-face educational intervention with an informational brochure for 43 informal caregivers of chronically or seriously ill older adults (50+) with cognitive impairment, recruited from communities in West Alabama. Their level of knowledge about palliative care was assessed by the Palliative Care Knowledge Scale (PaCKS). The pre- and post-test scores were compared by the Wilcoxon signed-ranks test, and the racial subgroup (Whites vs. Blacks) comparison was made by the Mann–Whitney U test. Results: There was a statistically significant difference between the pre- and post-test scores (z = 5.38, p < 0.001), indicating a statistically significant effect of the educational intervention in improving palliative care knowledge among participants. There was a significant difference (U = 143, p < 0.05) between Whites and Blacks in the pre-test, which, however, disappeared in the post-test (U = 173.50, p > 0.05), suggesting that the amount of increased PaCKS scores were significantly greater for Blacks (Mdn = 9.50) than for Whites (Mdn = 4.00, U = 130.50, p < 0.05). Significance of results: This study demonstrated that a one-time educational intervention can improve the level of palliative care knowledge among informal caregivers of chronically or seriously ill older adults with cognitive impairment, particularly among Black caregivers. Therefore, further educational efforts can be made to promote palliative care knowledge and reduce racial disparities in palliative care knowledge and its use.