Purpose: In this study, the authors 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 (L1)- and second-language (L2) 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. (Contains 3 tables, 1 figure, and 3 footnotes.)