While Dutch welke ‘which’-questions are structurally ambiguous, number agreement cues can disambiguate them. Despite such agreement cues, children misinterpret object questions as subject questions (Metz et al. 2010, 2012; Schouwenaars et al. 2014). We investigated if adding another cue, specifically, topicality in a discourse context, helps the interpretation of which -questions in two groups of Dutch children (5;5, n = 15 and 8;5, n = 21). Using a referent-selection task, we manipulated number on the verb and postverbal NP to create unambiguous wh- questions. Moreover, the questions were preceded by a discourse which established a topic, relating either to the wh- referent or the postverbal NP referent. Nevertheless, both 5- and 8-year-olds misinterpreted object questions as subject questions, ignoring the number and topicality cues to resolve the (local) ambiguity of which- questions. Our results confirm the effect of a subject-first bias in children’s interpretation of wh- questions. We conclude that topicality, in combination with number agreement, is not strong enough to overrule this subject-first bias.