The study aimed to identify the levels of both cognitive biases and decision-making among first-year secondary school students. It also sought to examine gender differences in these variables and to determine whether decision-making can be predicted based on cognitive biases (both dimensions and total score). To achieve this, a random sample of (115 male and 130 female) first-year secondary school students was selected. The study utilized the Cognitive Biases Scale by Van der Gaag et al. (2013), adapted into Arabic by the researcher, and the Decision-Making Scale developed by the researcher. Using appropriate statistical methods, the results indicated a moderate level of cognitive biases (total score and dimensions), except for the belief inflexibility dimension, which was at a low level. Additionally, students demonstrated a high level of decision-making ability. The findings also revealed no significant gender differences in the total cognitive biases score and the dimensions of attention for threat and external attribution. However, significant differences were found in the remaining dimensions in favor of males. Furthermore, significant gender differences were observed in decision-making, favoring females. The results also indicated that decision-making can be predicted based on cognitive biases and their dimensions.