Two preregistered experiments (N = 218) investigated children's developing ability to respond reasonably to disagreement. U.S. children aged 4-9, and adults (50% female, mostly white) formed an initial belief, and were confronted with the belief of a disagreeing other, whose evidence was weaker, stronger than, or equal to participants' evidence. With age, participants were increasingly likely to maintain their initial belief when their own evidence was stronger, adopt the other's belief when their evidence was weaker, and suspend judgment when both had equally strong evidence. Interestingly, 4- to 6-year-olds only suspended judgment reliably when this was assessed via the search for additional information (Experiment 2). Together, our experiments suggest that the ability to respond reasonably to disagreement develops over the preschool years.