Is the progression of secularization similar throughout the world? Younger generations in most countries tend to be less religious than older generations, but the extent of these differences varies greatly across countries and measures of religiosity. Little is known as to why this variation occurs. We explain and test this variation with a general secular transition model, which is based on data from Pew Research Center surveys in 111 countries as well as WVS/EVS data from 58 countries surveyed recently and 18 surveyed across at least four waves. Differences in religiosity among cohorts appear in three stages: first in participation in public rituals, second in giving religion importance in one’s life, and third in nominal belonging (the P-I-B sequence). This model fits the data across continents, encompassing countries with Christian, Buddhist, Hindu, and Muslim background. While historically Muslim nations are in the initial phases of secular transition, they still align with the model’s predictions. Eastern post-Soviet countries deviate from the predictions of the model. Overall, the findings suggest that a general pattern of secularization is at work around the world.