The morphological configuration of a word refers to the organization of the morphemes, which can vary both within and across languages. It is variable for example in two-digit number names (like twenty-one, is the decade or the unit named first) or in compound words (like spiderweb, is the modifier or the head named first). In this study, we combined repeating vs. switching the morphological configuration and language switching. In three experiments (Ns = 48), participants switched between languages in either a language-production task (i.e., naming two-digit numbers or compound words) or a language-comprehension task (i.e., typing an auditorily presented two-digit number). In all experiments, a language-repetition benefit was mainly observed when also the morphological configuration repeated from one trial to the next. In a fourth experiments (n = 48), participants were asked to translate an auditorily presented two-digit number. Thus, each trial included a language switch between the source language (always English) and the target language (German or Spanish). Additionally, the target language could repeat or switch in two subsequent trials. Again, a benefit of repeating the (target) language from one trial to the next was influenced by repeating vs. switching the morphological configuration of the words. The (target) language-repetition benefit was reduced (or even reversed) by a morphological configuration switch 1) in the source language from trial to trial and 2) from the source to the target language. Taken together, these experiments demonstrate that grammatical information as the morphological configuration play a critical role in language switching.