The study aimed to reveal the effect of nationalism, historical knowledge, religious moderation, Islamism, and radical thinking on
radical behavior of the young generation in public high schools in Padang, West Sumatra, Indonesia. The samples were grade XII
students from four schools out of 16 schools. All indicators met the requirements of the validity and reliability test with Cronbach’s
alpha and confirmatory factor analysis (CFA). Convergent validity test (variance extracted (VE) ≥ 0.50) obtained three constructs
that meet the requirements to proceed to the analysis structure mode. The finding showed that nationalism construct did not affect
the radical behavior construct with Sig. 0.203 > 0.05, while religious moderation construct did not affect radical behavior construct
with Sig. 0.629 > 0.05. Meanwhile, the results of the multiple regression analysis showed that the constructs of nationalism and
religious moderation simultaneously did not affect the construct of radical behavior. The finding illustrated that public high school
students in Padang had a good understanding of nationalism and a moderate attitude in religious life so that there was no potential
for the radicalism behavior among the young generation, especially for public high school students in Padang, West Sumatra. The
practical implication of this research is that the school leaderships will formulate controlled regulations regarding the implemen-
tation of religious and clerical activities carried out by the Intraschool Student Organization (ISSO). In short, they will not be
infiltrated by radical ideas from external parties.