Posterror slowing (PES) refers to an increased response time following errors. While PES has traditionally been attributed to control adjustments, recent evidence suggested that PES reflects interference. The present study investigated the hypothesis that control and interference represent 2 components of PES that differ with respect to their time course and task-specificity. To this end, we investigated PES in a dual-task paradigm in which participants had to classify colors and tones that were separated by a variable stimulus onset asynchrony (SOA). Errors in the color task caused PES both in the tone task of the same trial and the color task of the subsequent trial. However, while the former effect disappeared with an increasing SOA, the latter effect was independent of SOA and lasted for several trials. This suggests that errors simultaneously induce task-unspecific, transient PES reflecting interference and task-specific, more long-lasting PES reflecting control adjustments.