Late/Terminal Classic Maya ballcourts from the upper Grijalva Basin (Chiapas, Mexico) are described and analyzed in a regional settlement and political context. The upper Grijalva Basin is found to have large numbers of ballcourts compared with other parts of the Maya area. The spatial distribution of ballcourts in the basin matches the distribution of civic-ceremonial centers, reflecting the key ritual and political roles of the ballcourt. Absence of a clear hierarchy in size or elaboration among the ballcourts reflects political decentralization. Ballcourt sizes, forms, alignments, and placements indicate their use for either Maya or Mexican hip ball games or more likely some combination of the two game types. Finally, three models that focus on elite factions, elite wealth building, and ritualized conflict are used to explore why the upper Grijalva Basin has so many more ballcourts compared with neighboring parts of the Maya area. An elite-factions model, incorporating a high degree of decentralization across the political landscape, is selected as most plausible for understanding the basin's proliferation of ballcourts.