This study investigates clitic omission in Portuguese-Spanish bilingual children, comparing them to monolingual children. Children in the target group were simultaneous bilinguals between 3 and 5 years old, living in Portugal and attending a Spanish school. Bilinguals were administered two versions of a production test, which elicited clitics in three different contexts: (i) accusative third person in simple sentences; (ii) accusative third person in adjunct islands; (iii) reflexive third person in simple sentences. Results show that the rates of omission in the bilinguals’ Spanish are higher than in Spanish monolinguals, but bilinguals distinguish the two languages and the different contexts: omission is higher in Portuguese than in Spanish, and higher with accusatives in simple sentences than in the other contexts.