One of the cues that children might use in learning words is the level of certainty that speakers demonstrate in their naming of a novel object. This study presented 52 4–5 year old Dutch children with a word-learning task in which two puppets each used the same label for a different novel object. In three conditions, puppets expressed their level of speaker certainty lexically (e.g. ‘I know this is a mit’ vs. ‘I think this is a mit’), they used discourse means to convey certainty (e.g. ‘I play with this a lot. Yes, a mit’, vs. ‘I’ve never played with this. Well, a mit’) or they combined the two. In all conditions, children were more likely to pick the object referred to by the more certain puppet as the referent of the new word, demonstrating that speaker certainty is a relevant cue in the word learning process.