In two picture-naming experiments we examined whether bilinguals co-activate the non-target language during word production in the target language. The pictures were presented out-of-context (Experiment 1) or in visually presented sentence contexts (Experiment 2). In both experiments different participant groups performed the task in Dutch, their native language (L1), or in English, their second language (L2). The pictures’ names were Dutch–English cognates or non-cognates, the cognate effect serving as the marker of activation of the non-target language. In Experiment 2 we also examined the effect of sentence constraint. In both experiments a cognate effect occurred, but it was modulated by language and sentence constraint: The effect was larger in L2 than in L1, larger with low-constraint sentences than with high-constraint sentences, and disappeared in the high-constraint L1 condition. These results extend earlier bilingual word-recognition and out-of-context production studies, suggesting that also during word production in context, co-activation of the non-target language occurs.