Childrens causal learning from intentional actions (i.e., interventions) can be dramatically affected by the psychological and social circumstances in which they are produced. A context fundamental to childrens learning across many domains is joint activity; however little is known about childrens causal learning with others. Collaborative settings with shared goals and action plans might facilitate childrens learning from their own and a partners coordinated actions (Sommerville & Hammond, 2007). Alternatively, childrens own interventions may be more informative than those produced by a partner (Kushnir, Wellman, & Gelman, 2009). To address these issues, young children learned about simple causal systems via interventions performed: 1) by themselves, 2) by an experimenter, or 3) jointly with an experimenter. Childrens subsequent causal knowledge, source-memory, and free play are compared across these collaborative contexts. Findings may provide guidance about structuring learning environments.