Determinants of pro-environmental behaviors among Iranian High School students using the theory of planned behavior and locus of control

The environment is one of the key determinants of health and well-being. Humans play a central role in creating, maintaining, and promoting a health-supportive environment. On the other hand, promoting pro-environmental behaviors is one of the fundamental challenges for educational systems in societies. Understanding and analyzing these behaviors based on scientific theories is a crucial step for designing appropriate educational interventions, and schools provide a structured environment for the development and implementation of environmental education. Therefore, this study aimed to identify the determinants of pro-environmental behaviors among Iranian high school students Using the Theory of Planned Behavior and Locus of Control. This analytical cross-sectional study involved 410 middle school students in Shiraz, selected through cluster sampling. Data were collected using a researcher-made questionnaire based on the Theory of Planned Behavior and Locus of Control, with a Cronbach’s alpha above 0.80 and external reliability above 0.75. Data were analyzed using SPSS 27 software, employing Pearson correlation and linear regression tests. The results indicated no significant differences between girls and boys in the constructs of the Theory of Planned Behavior, except for Locus of Control, where boys scored higher (26.17 ± 3.84 vs. 27.04 ± 4.24, p = .030). Pro-environmental behaviors were most strongly correlated with subjective norms ( r = .485, p < .01) and attitudes ( r = .352, p < .01). Multiple regression analysis showed that subjective norms, perceived behavioral control, intention, locus of control, and attitude were the main predictors of behavior, whereas knowledge was not a predictor. Among these predictors, subjective norms (β = 0.341, p < .001) were the strongest predictor of pro-environmental behaviors, followed by perceived behavioral control (β = 0.147, p = .001), intention (β = 0.125, p = .007), locus of control (β = 0.119, p = .005), and attitude (β = 0.097, p = .047), While Knowledge was not a significant predictor of pro-environmental behaviors in the present regression model, pro-environmental behaviors among students were more strongly associated with subjective norms, positive attitudes, and a sense of personal control than with knowledge. Therefore, it is recommended that schools identify and strengthen these determinants before designing educational interventions, to enhance effectiveness and promote sustainable behavioral change.