The current study explores the relationship between metalinguistic awareness -- specifically phonological awareness, morphological awareness, and orthographic knowledge -- and vocabulary knowledge within and across two languages, German (L1) and Arabic (L2), in bilingual children in Germany (N = 58). Phonological awareness emerged as a predictor of vocabulary knowledge in both languages, though its influence varied by language, with a stronger correlation in German. Arabic orthographic knowledge contributed significantly to vocabulary knowledge beyond phonological awareness in both languages. In contrast, German orthographic knowledge predicted vocabulary knowledge only in German. Morphological awareness did not significantly predict vocabulary knowledge in either language. These findings are discussed in terms of orthographic depth, morphological structure, and cross-linguistic variations between Arabic and German.