AbstractObjectives:Performing high-quality and reliable cognitive testing requires significant resources and training. As a result, large-scale studies involving cognitive testing are difficult to perform in low- and middle-income settings, limiting access to critical knowledge to improve academic achievement and economic production in these populations. The NIH Toolbox® is a collection of cognitive, motor, sensory, and emotional tests that can be administered and scored using an iPad® tablet, reducing the need for training and quality monitoring; and thus, it is a potential solution to this problem.Methods:We describe our process for translation and cultural adaptation of the existing NIH Toolbox tests of fluid cognition into the Swahili and Dholuo languages for use in children aged 3–14 years in western Kenya. Through serial forward and back translations, cognitive interviews, group consensus, outside feedback, and support from the NIH Toolbox team, we produced translated tests that have both face validity and linguistic validation.Results:During our cognitive interviews, we found that the five chosen tests (one each of attention, cognitive flexibility, working memory, episodic memory, and processing speed) were generally well understood by children aged 7–14 years in our chosen populations. The cognitive interviews informed alterations in translation as well as slight changes in some images to culturally adapt the tests.Conclusions:This study describes the process by which we translated five fluid cognition tests from the NIH Toolbox into the Swahili and Dholuo languages. The finished testing application will be available for future studies, including a pilot study for assessment of psychometric properties.