The importance of self-assessment and critical thinking in students’ learning process is well established, however, few studies have evaluated the perceptions of university students regarding the effects of self-assessment on their critical thinking learning styles. This study aimed to measure the perceptions of university students about the effects of self-assessment on their critical thinking learning style. By using a quantitative descriptive research design, data were collected from 243 students enrolled in BS education program at university of Malakand, Khyber Pakhtunkhwa, Pakistan. The data from the sampled group was measured through self-developed questionnaire comprising 24 items covering different aspect of critical thinking learning style and self-assessment. The questionnaire was pilot tested and after the estimation of reliability and validity the data were collected from the sampled group. Descriptive and inferential statistical techniques such as Mean scores, standard deviations and Chi-square test were used for the analysis of data. The collected data were analyzed by using SPSS version 20. The major findings of the study suggested that critical thinking helps students improve learning and cultivates among them the ability of making choices and guides them to understand problems. It was confirmed that self-assessment improves the understanding of students to identify and solve their learning problems. The students strongly agreed that self-assessment promoted their understanding of course content. It is suggested that future research may use the results of the study as a basis for improving the critical learning outcomes of students and incorporate self-assessment as a technique in the teaching process.