The objective of the study conducted at Qatar University is to assess the impact of different leadership styles on the effectiveness of decision-making. To address the variables of the study, a descriptive-analytical method was employed by the researchers. The study population consisted of a total of 95 employees, out of which a random sample of 78 employees from Qatar University was selected. The study instrument used is a questionnaire. Consequently, data is collected, analyzed, and hypotheses are tested using the Statistical Package for the Social Sciences (SPSS). The study yields several conclusions, the most significant being that the level of leadership styles, including democratic, lenient, and autocratic, at Qatar University is found to be average. Similarly, the level of decision-making effectiveness, encompassing problem identification, information gathering, alternative generation, and alternative selection, is also determined to be average at Qatar University. Furthermore, a statistically significant effect is observed at a significance level of α = 0.05, indicating that leadership styles, with their dimensions, had an impact on decision-making effectiveness, with its dimensions, at Qatar University. Based on the findings, the study puts forth several recommendations, including the encouragement of adopting and implementing leadership styles at Qatar University, motivating officials to devise mechanisms for adhering to leadership styles, fostering the exchange of experiences with esteemed educational institutions to enhance the application of leadership styles, and bolstering the decision-making process.