We studied English-learning children's ability to learn the meanings of novel words from sentences containing truth-functional negation (Exp1) and to use the semantics of negation to inform word meaning (Exp2). In Exp1, 22-month-olds (n = 21) heard dialogues introducing a novel verb in either negative-transitive "("Mary didn't blick the baby")" or negative-intransitive "("Mary didn't blick")" sentences. When then asked to "Find blicking!" while viewing two-participant versus one-participant actions, children who heard negative-transitive sentences looked longer at the two-participant event than children who heard negative-intransitives. Thus, the mere presence of negation does not disrupt sentence processing and word learning in young children. Experiment 2 tested whether 2-to-4-year-olds (n = 20) use the semantics of negation to restrict the meaning of novel nouns when categorizing objects varying along a perceptual continuum (from 10 to 90% exemplars). Children initially heard ""These are blickets"" paired with certain exemplars (e.g., yellowish creatures, exemplars 10 and 30%). They then saw additional exemplars (e.g., pinkish creatures, 70 and 90%) while hearing either ""These are not blickets"" (negative condition) or ""These are also blickets"" (affirmative condition). At test, when seeing two novel exemplars from the continuum (e.g., creatures 20 and 80%) and asked to find "a blicket," children in the negative condition selected the exemplar from the bottom of the continuum (i.e., the 20%) more often than children in the affirmative condition. Thus, English-learning children as young as 22-months of age correctly parse negative sentences and 2-to-4-year-olds can use negation to understand the boundaries of a word's meaning.