Individuals‟ thinking styles play central role in their decision making process. Epstein, Pacini, Denes-Raj, and Heier, (1996) and Pacini and Epstein (1999) described two major types of thinking patterns i.e. rational and experiential. Prior research investigated different factors that affect thinking styles of people. These factors range from inherited instincts to environmental pressures. The current study aimed to examine the impact of religious affiliations of secondary school students on their rational thinking. Profound review of related literature leaded the researcher to adapt age-universal I-E scale developed by Allport and Ross (1967) and revised by Kirkpatrick, Moberg, and Lynn (1988) and rational experiential inventory for adolescents (REI-A) developed by Pacini and Epstein (1999) and revised by Marks, Hine, Blore, and Phillips (2008). The age universal I-E scale measures three dimensions of religiousness i.e. intrinsic, extrinsic personal and extrinsic social religiosity of the individuals of all ages. The REI-A is to scale rational and experiential thinking of adolescents. The 3517 secondary school students having religious affiliations with Hinduism (1050), Christianity (1073) and Islam (1394) were included in the sample using non-random sampling techniques. It was ensured that only the students studying government prepared syllabus were selected in the samples. The adapted instruments were translated into Urdu and validated through the opinions of ten field experts. All five subscales demonstrated high reliability of the data of Pakistani samples. Collected data were entered in SPSS files. The negative statements were recoded and results were presented in graphs and tables. Results of skewness, Kurtosis, Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy and Bartlett‟s test of sphericity supported the normality of sample distribution and homogeneity of data. Principal component analysis, rotated component matrix and structural equation models endorsed the structures of scales and subscales. Statistical analysis of the data was done using t test, ANOVA, correlation coefficients and regression analysis. Findings revealed that Muslim secondary school students were comparatively more intrinsically religious and rational in thinking than their Hindu and Christian fellows. In contrast the Christian students were comparatively more extrinsic personal and extrinsic social religious than their Hindu and Muslim secondary school fellows. Similarly, the Christian students were more experiential in thinking than their fellows. Major contribution of xvi the study was to trace out the relationship between religious orientations and thinking patterns of the students. It was concluded that rational thinking of Hindu, Christian and Muslim secondary school students (separately and collectively) was directly associated with their intrinsic and extrinsic personal religiousness and indirectly correlated with their extrinsic social religiosity. The three aspects of religious orientations moderately explained the variances in rational thinking of the Hindu and Muslim secondary school students whereas for the Christian students this share was significantly small. The study proposed further research in the field to investigate the factors (social, cultural, political, financial etc.) that played role in forming religious orientations of the students having different faith. The study also suggests further investigation of factors that transform students thinking styles with the passage of time.