Many studies have explored how Language-Minority Bilingual Children (LMBC) read and comprehend, while the way they learn to spell and write has received less attention. This study aimed to assess a comprehensive profile of spelling and writing skills in LMBC, comparing performances of 4th and 5th grade bilingual (n = 74) and monolingual (n = 131) children in word and nonword reading and multilevel spelling and writing tasks (word, nonword and passage dictation, and written narrative production). Furthermore, we explored the role of linguistic and cognitive predictors (nonverbal Intellectual Quotient, verbal knowledge, morphosyntactic comprehension, nonword repetition) in spelling and writing outcomes. Our findings showed that, overall, LMBC did not reach a monolingual-like proficiency in spelling by the end of primary school, while they were similar to monolinguals in reading tasks and were able to produce written narratives with adequate macrostructure, syntactic complexity, and lexical variety. Moreover, morphosyntactic comprehension predicted spelling in both groups. Nonverbal intelligence and verbal knowledge predicted spelling skills only for the bilingual group. With regards to writing skills, morphosyntactic comprehension emerged as a predictor exclusively in the bilingual group. These results are discussed with reference to educational and clinical implications.