<p style="text-align: justify;"><strong>Objective. </strong>Exploration of the psychological factors of conflict-related action among Sundanese Muslim students in Indonesia. <br><strong>Background. </strong>Religious-based conflicts have been widely examined in various disciplines, attracting responses and factors in every cultural context. <br><strong>Study design. </strong>Study 1 used an indigenous-based survey and was analyzed by thematic analysis. Study 2 examined the role of political ideology and perceived injustice in conflict-related behavior using hierarchical regression analysis. <br><strong>Participants. </strong>Study 1: 224 people (35,7% of men, 64,3% of women) from 18 to 49 years old (<em>M </em>= 20,98; <em>SD</em> = 3,72). Study 2: 494 people (35,6% of men, 64,4% of women) from 17 to 49 years old (<em>M</em> = 20,00; <em>SD</em> = 1,52).<br><strong>Measurements. </strong>Indonesian-language versions of the scales of religious fundamentalism ideology by Muluk and colleagues, violent extremist attitude by Nivette and colleagues, nonviolent direct action by Brown and colleagues, and sensitivity to injustice by Schmitt and colleagues. <br><strong>Results. </strong>Study 1 showed specific patterns of cognitive, emotional, and behavioral responses. There are differences in the respondents' responses to conflicts between and within religions. These differences are caused by ideology orientation towards religion and perception of injustice towards their groups. Study 2 confirmed Study 1 that religious fundamentalism predicts both violent and nonviolent behavior. Also, perceived injustice of victims moderates the effect of religious fundamentalism to violent behavior. Meanwhile, perceived injustice of perpetrators predicts only nonviolent behavior. <br><strong>Conclusions. </strong>There is a significant effect of religious-based ideology and perceived injustice on conflict-related behavior in the Sundanese Muslim context.</p>