Over the last twenty-five years the constitutional landscape of Southeast Asia has changed tremendously. As in the rest of the world, states in the region are dramatically altering their constitutions, often putting in place institutional safeguards for individual rights, such as constitutional courts and human rights commissions. Yet despite the numerous formal changes, actual constitutional practice in the region has been highly uneven. Four areas are particularly contested: constitutional drafting and design; individual and religious rights; the role of the military in constitutional politics; and the rule of law, courts and justice. How states in Southeast Asia resolve unfolding conflicts in these four areas will be critical to how constitutionalism evolves in the region. Replacing traditional legal scholarship with a new perspective on how constitutional politics are contested in the region, this article seeks to advance the scholarly debate by delving deeply into the dynamics that underpin unfolding constitutionalism trajectories and assessing whether countries in the region are actually deepening constitutional practice in a Western liberal sense or whether the model that seems to be emerging is quite different.