[en] PURPOSE: This study explored the impact of test language and cultural status on vocabulary and working memory performance in multilingual language minority children. METHOD: Twenty 7-year-old Portuguese-speaking immigrant children living in Luxembourg completed several assessments of first- and second-language vocabulary (comprehension and production), executive-loaded working memory (counting recall and backward digit recall), and verbal short-term memory (digit recall and nonword repetition). Cross-linguistic task performance was compared within individuals. The language minority children were also compared with multilingual language majority children from Luxembourg and Portuguese-speaking monolinguals from Brazil without an immigrant background matched on age, sex, socioeconomic status, and nonverbal reasoning. RESULTS: Results showed that (a) verbal working memory measures involving numerical memoranda were relatively independent of test language and cultural status; (b) language status had an impact on the repetition of high- but not on low-wordlike L2 nonwords; (c) large cross-linguistic and cross-cultural effects emerged for productive vocabulary; (d) cross-cultural effects were less pronounced for vocabulary comprehension with no differences between groups if only L1-words relevant to the home context were considered. CONCLUSION: The study indicates that linguistic and cognitive assessments for language minority children require careful choice among measures to ensure valid results. Implications for testing culturally and linguistically diverse children are discussed.