One of the main factors that affect academic achievement is individual differences. There are several different paradigms that have been proposed for understanding these differences, such as psychometric, Piagetian or Vygotkskian approaches. In 1970s researchers started to study on the roles of thinking styles in learning. A well known comprehensive thinking style theory was proposed by Sternberg (1988). According to the 'Theory of Mental Self- Government' people govern and manage every day activities in different styles with which they are comfortable. This theory describes 13 thinking styles in 5 dimensions: (a) functions: executive, legislative, judicial, (b) forms: monarchic, hierarchic, oligarchic, anarchic, (c) levels: local, global, (d) scope: internal, external, (e) leaning: liberal, conservative. Some students might be somewhat flexible in their use of styles and try with varying degrees of success to adapt themselves to the stylistic demand of a given course. Also a student with one preference in one situation may have different preferences in another situation. In addition styles may chance with time and with life demands. Thinking styles can be modified by the environment in which people reside. The students prefer especially a type of style in courses and can be more successful in specific type of instruction and assessment procedures. An executive - type student might benefit more from acceleration, where the same material is presented at a more rapid pace. However legislative-type student might benefit from enrichment, where the opportunity to do creative projects would be consistent with student's preferred style of working. Also lecture as a most common form of instruction in schools is beneficial for the executive and hierarchical-type of students. Similarly most of the teachers prefer multiple - choice test to assess and evaluate their students. But this type of testing is very much oriented toward executive and local thinkers. It is necessary that schools take into account the fits between teacher and students, principal and teachers and also between the way a subject is thought and assessed and the way a student thinks. The primary goal of this study is to investigate the contribution of thinking styles to academic achievement. Also to understand the nature of thinking styles it was examined the relationship between thinking styles and students' personal and situational characteristics and aspects of psychological domain (locus of control), their social skills such as interpersonal relations, self-esteem and empathy, as well as creativity and critical thinking abilities. The thinking styles of the students were assessed by the 'Thinking Styles Questionnaire' developed by Sternberg and adapted into Turkish by Palut (2003). In order to determine social skills of the students the 'Social Skills Scale' developed by Palut, Aydin and Derelioglu (2000) was used. 'Torrance Creativity Test' and Watson - Glaser Critical Thinking Appraisal ( WGCTA) were utilized to determine the students' creativity and critical thinking abilities. Finally Rotter's Internal -External Locus of Control Scale' adapted into Turkish by Dagli (1991) was administrated to the students. The students' university entrance exam and grade point average scores were used to determine academic success. 250 student teachers in Marmara University, Atatürk Education Faculty and 100 students attending to preparatory courses to pass the university entrance exam participated in this study. The data will be analyzed in SPPS program.