Naturalistic polyadic family conflicts (i.e., involving three or more members) were studied over a 2-year period by comparing disputes originating between siblings (sibling-originated) or a parent and child (parent-child-originated). Conflicts were coded for (a) origination, (b) topic, (c) resolution, and (d) power in 39 families with two children when both were 2 and 4 years old (T1) and again at 4 and 6 years of age (T2). Greater proportions of sibling-originated and parent-child-originated conflicts were observed at T1 and T2, respectively. In sibling-originated conflicts, time-related variations for ownership and controlling behaviors were apparent.