Recently many authors have stressed that domain-general cognitive processes may affect performance in linguistic tasks. This challenges the traditional view that speaking and listening are fairly modular processes. Going beyond this broad claim, we aim to determine exactly how domain-general processes influence linguistic processes. In the present study we examined the influence of selective inhibition (invoked to suppress responses to potent competitors to target stimuli and taking some time to build up) on performance in two classic word production tasks, the semantic blocking task (naming sets of objects that do vs. do not belong to the same semantic category) and the pictureword interference task (naming pictures accompanied by categorically related vs. unrelated words). Both tasks were completed by the same participants. Analyses of the size of the interference effects for fast and slower responses (using delta plots) and of the correlations of the effect sizes in the two tasks demonstrated that selective inhibition was recruited in both tasks. We propose that the process supported by selective inhibition is lemma selection. We discuss the implications for theories concerning the origin of the interference effects in the two paradigms and the nature of lexical selection processes.