The inhibition of irrelevant tasks is considered an important cognitive control process involved in human multitasking performance. In a task-switching situation, inhibiting the no longer relevant task facilitates switching to the currently relevant task. In this talk I will present research on task-level inhibition using behavioral measures and diffusion modeling. Applying the diffusion model allows for investigating the cognitive mechanisms underlying performance on a more fine-grained level. I will present studies on age-related changes of task inhibition, on affective modulations of task inhibition and conflict adaptation, and on aftereffects of task inhibition. I will also present an integrative theoretical perspective, arguing that these and other sequential effects in task-switching can be viewed as instances of conflict-control loops in multitasking, facilitating flexible trial-by-trial adjustment of cognitive control.