Purpose: This study evaluated a newly developed quasi-universal nonword repetition task (Q-U NWRT) as a diagnostic tool for bilingual children with language impairment (LI) who have Dutch as a second language. The Q-U NWRT was designed to be minimally influenced by knowledge of one specific language, in contrast to a language-specific (L-S) NWRT to which it was compared. Methods: 120 monolingual and bilingual children with and without LI participated (30 per group). A mixed-design ANOVA was used to investigate the effects of LI and biling84953339567ualism on the NWRTs. Receiver Operating Characteristic analyses were conducted to evaluate the instruments' diagnostic value. Results: Large negative effects of LI were found on both NWRTs, whereas negative effects of bilingualism only occurred on the L-S NWRT. Both instruments had high clinical accuracy in the monolingual group, but only the Q-U NWRT had high clinical accuracy in the bilingual group. Conclusions: This study indicates that the Q-U NWRT is a promising diagnostic tool to help identify LI in bilingual children learning Dutch as a second language. The instrument was clinically accurate in both a monolingual and bilingual group of children and seems better able to disentangle language impairment from language disadvantage than more language-specific measures.