This study aimed to test the effects of countermarketing videos addressing common misperceptions about ingredients and claims on children’s sugary drinks. An online randomized controlled experiment was conducted in January 2021 with US caregivers (n = 600) of young children (aged 8‒37 months) to assess the effects of watching countermarketing versus control videos on intentions to serve sugary and healthy drinks (6-point scales) and attitudes (10-point scales) about fruit drinks and toddler milks. The countermarketing videos significantly reduced positive attitudes about fruit drinks (mean difference = 0.92) and toddler milks (mean difference = 2.10), reduced intentions to serve both (mean difference = 0.50 and 0.92, respectively), and increased intentions to serve plain milk (mean difference = 0.52) versus control videos (all Ps < .001). The videos were more effective for toddler milks versus fruit drinks, and effects on fruit drink intentions were greater for Black versus White caregivers and caregivers of children aged 24 months or younger.