The 1990s saw economic growth on American Indian Reservations outpace the growth of the US economy by about a factor of three (Taylor & Kalt, 2005). In the 2000s, the pace of growth cooled, but reservation economies still gained ground against the national trend (Akee & Taylor, 2014). Self-determination policies—particularly tribes’ investments in casinos and related businesses—get most of the credit in the public’s perception, but this two-decade period is also characterized by widespread institutional change. Self-determination has meant that Native communities displaced the Bureau of Indian Affairs as the primary developer and/or approver of constitutions, with potentially large consequences for governing effectiveness and development success. This paper joins three new datasets on: i) tribe-state gaming compacts; ii) gaming facilities; and iii) constitutional reforms to decompose the contributors to growth over the period and identify the role of institutions and culture in development. Given that the gap between Indian incomes and the national average still remains large, this work promises to point to essential strategies to keep the pace of economic growth from slowing.