Learning to plan sequences of actions and appropriately adapt our actions during interactions with others are both critical skills upon which much of human society is built. We know that children’s joint action and planning skills are both undergoing development during the preschool years, but not much is known about how the joint action context influences young children’s planning. In this study, we examined the effect of playing alone or with a joint partner on sequence planning during a problem-solving game in three-year-old children. We found that children were better at planning ahead in the individual than the joint condition of the game despite the joint condition requiring fewer actions on the part of the child. In contrast, children were equally good at problem-solving (i.e., correcting an error) in both conditions. The possible reasons for this difference and directions of future research are discussed.