This study examined the social organization of Guatemalan Mayan fathers' engagement with school-age children in a group problem-solving task. Twenty-nine groups of Mayan fathers varying in extent of Western schooling and 3 related school-age children (ages 6-12 years) constructed a puzzle together. Groups with fathers with 0 to 3 grades more often constructed the puzzle through shared multiparty collaboration involving a common agenda, whereas groups with fathers with 12 or more grades more often structured their contributions through a division of labor. Groups involving fathers with 6 to 9 grades demonstrated patterns of coordination that fell between the other two types of schooling groups. Fathers with greater schooling were also found to propose more explicit division-of-labor plans to children than were fathers with no to little schooling. The results indicate that Western schooling may be gradually transforming the collaborative social organization of group problem solving of indigenous Mayan families. (Contains 3 tables and 1 figure.)