The current research is designed to figure out the degree of a training program which depended on brain based-learning theory in developing critical thinking skills among university students at university. The proposed training program worked as independent variable and consisted of (20) training sessions, the methodology of the proposed program depended on the integrity between (Caine and Caine)’s principles of brain-based learning and (Karen D. Olsen, Susan Kovalik)’principles of brain-compatible learning. The dependent variable was critical thinking which consisted from (5) skills as follows: Inference, recognition of assumptions, deduction, interpretation, and evaluation of arguments. Validity and reliability of both independent and dependent variables were checked and confirmed by pilot study, the initial pilot study included (185) participants (90 males, 95 females) among university’s students with different major backgrounds/specializations. The final study was divided into two groups; first of all: Controlled group which consisted of (38) participants; (11 males, 27 females), and second group was experimental group which consisted of (38) participants; (16 males, 22 females) both with average age (20 Yrs.), the research design depended on quasi-experimental design in case of equivalence between the two groups. The most important results showed the existence of a statistically significant difference at the level of (0.01) between the mean scores of the experimental group and the control group in critical thinking skills for the benefit of post mean scores of the experimental group, there is a statistically significant difference at the level of (0.01) between the mean scores of both pre and post experimental group in a critical thinking skills in favor of post-experimental test, and there are no statistically significant difference between the mean scores of the post-experimental test and its followed test. The researcher recommended: Use training program based on brain-based learning theory in all universities, and training faculty members to employ it.