Objective: This study examined the relationship between cortical thickness in executive control networks and neuropsychological measures of executive function. Method: Forty-one community-dwelling older adults completed an MRI scan and a neuropsychological battery including 5 measures of executive function. Results: Factor analysis of executive function measures revealed 2 distinct factors: (a) Complex Attention Control (CAC), comprised of tasks that required immediate response to stimuli and involved subtle performance feedback; and (b) Sustained Executive Control (SEC), comprised of tasks that involved maintenance and manipulation of information over time. Neural networks of interest were the frontoparietal network (F-P) and cingulo-opercular network (C-O), which have previously been hypothesized to relate to different components of executive function, based on functional MRI studies, but not neuropsychological factors. Linear regression models revealed that greater cortical thickness in the F-P network, but not the C-O network, predicted better performance on the CAC factor, whereas greater cortical thickness in the C-O network, but not the F-P network, predicted better performance on the SEC factor. Conclusions: The relationship between cortical thickness and performance on executive function measures was characterized by a double dissociation between the thickness of cortical regions hypothesized to be involved in executive control and distinct executive processes. Results indicate that fundamentally different executive processes may be predicted by cortical thickness in distinct brain networks.