One of the most widely accepted scholarly findings about welfare states is that democracies are more likely to have generous welfare states than autocracies. In democracies, voter preferences and interest group pressure create incentives for elected leaders to adopt generous social welfare policies. Social welfare provision in autocracies is limited, scholars contend, because authoritarian governments are not accountable to voters and repress interest groups. Yet contrary to theoretical expectations, some autocracies in the Middle East and North Africa have adopted comprehensive social programs that have considerably improved the well-being of their citizens. In this paper, I advance an argument to explain the emergence of these relatively generous authoritarian welfare states. I argue that generous authoritarian welfare states have emerged in countries where mass mobilizing parties (MMPs) and infrastructurally powerful states were present during the initial periods of authoritarian regime formation. MMPs are political parties that emerged during the colonial or imperial rule and that sought to fundamentally transform the established political order. These transformative goals required them to generate widespread support in societies that were deeply differentiated along ethnic, racial, and sectarian lines. To mobilize citizens behind the party’s transformational goals, MMPs sought to develop new national solidarities to supplant preexisting sectional identities. This, in turn, required regime-building MMPs to replace communal networks of social support with alternative, national systems of solidarity. To achieve this goal of cultivating national solidarity, MMPs adopted generous social programs that built a substantive bond between citizens and national parties. The development of generous authoritarian welfare states, however, is conditioned by the level of infrastructural power of the state. Building a state with high infrastructural power enabled regime-building MMPs to (1) raise revenues to finance social welfare policies, (2) acquire the bureaucratic capacity to design and implement these policies, and (3) gain autonomy from social groups that might oppose social welfare provision. I illustrate these logics through case studies of Egypt, Tunisia, and Turkey, three autocracies that have built relatively generous welfare states despite showing significant difference in factors that explain the generous social welfare provision, such as strong labor movements, communal cleavages, and intense conflict among the founding elites.