The ability to enact cognitive control under changing environmental demands is commonly studied using set-shifting paradigms. While the control processes required for task set reconfiguration (switch costs) have been studied extensively, less research has focused on the control required during task repetition in blocks containing multiple tasks as compared to those containing a single task (mixing costs). We investigated how individual differences in mixing costs related to other executive functions (EFs) in a large sample (N = 749) of young adults. Individual differences in mixing costs across three different set-shifting paradigms loaded significantly onto a mixing cost latent variable. This Mixing Cost factor moderately correlated with a Common EF factor capturing variance shared across nine EF tasks designed to tap response inhibition, working memory updating, and mental set-shifting. It did not correlate with Updating-Specific and Shifting-Specific factors. Results indicate that the additional cognitive control required during mixed-task block repeat trials relies on general executive processes, as well as unique abilities distinct from both set-shifting and working memory updating.