Aims and objectives: Prior research shows that bilingual pupils may have foreign language learning advantages over monolinguals, but evidence is controversial. Investigating English as a foreign language (EFL) in the context of the Netherlands, we hypothesized that the conflicting findings may be partly explained by differences in extramural EFL exposure. We further predicted that amount and length of EFL exposure might moderate the effects of bilingualism on EFL learning and cross-language relationships between English and the previously acquired languages. Approach: Twelve- to 14-year-old Turkish–Dutch bilinguals ( n = 30) and Dutch monolinguals ( n = 31) participated. The Peabody Picture Vocabulary Test was used to measure receptive vocabulary in English, Dutch, and Turkish. Grammatical ability was measured with a sentence repetition task. A questionnaire was used to obtain information on children’s language exposure. Data and analysis: Data were analyzed by means of multilevel linear regression. Amount and length of extramural exposure were used as control variables in the analyses comparing EFL skills of bilinguals and monolinguals. The role of exposure as a moderator of bilingual effects and cross-language relationships was also tested. Findings/conclusions: If differences in exposure were not taken into account, the bilinguals were outperformed by the monolinguals on EFL vocabulary, but not on grammar. However, the between-group difference disappeared once exposure measures were controlled for. Bilinguals with little exposure to English performed worse than monolingual peers, but at higher exposure levels, bilinguals outperformed monolinguals. In the bilingual sample, Dutch vocabulary predicted English vocabulary, but Turkish proficiency did not predict English skills. Originality: This is the first study to include measures of extramural exposure in investigating the effects of bilingualism on EFL learning. Significance/implications: This research shows that differences between monolingual and bilingual EFL learners can be either concealed or inflated if exposure is not controlled for. Furthermore, exposure moderates bilingual effects in EFL learning.