Whether executive system is a unified or separable structure is still a matter of debate. Using an individual differences approach, this study investigated the structure of five hypothesized executive functions (“Updating”, “Shifting,” “Inhibition”, “Dual-Tasking” and “Planning”) and their relationship to “Intelligence”. The separability of these executive functions was explored. Ten neuropsychological tests were administered to young and healthy participants (N =103). Correlations between tests that were expected to tap the same EF were low. Results of the Principal Components Analysis revealed nine components only 4 of which were clear enough to interpret in relation to previous literature. Overall results suggest some degree of separability of “Updating”, “Shifting” and “Dual-Tasking”, in addition to independence of all nine components from “Intelligence”. However there is some room for concern with regards to the overall reliability of these results (α = .487) and sample adequacy (KMO = .475).